I agree with what Jae and Pam have said.Also with Ernest who has posted since I started this.
I don't know whether a reflection I'm having lately will help too but I'll tell it just in case. Some recent things have been making me ponder over a long-ago experience.
I once felt very lonely when I was in my teens. I'm not sure now how long it lasted, it could have been a few months. I'd always liked being alone when I'd had the chance to be, I could enjoy myself whether I had someone with me or not, so I was somewhat puzzled by these feelings. One evening the answer - I expect I'd been praying for it but I can't actually remember - dawned on me : I was missing the friends from whom I'd been cut off when we left school. We'd been together for five years in what are now called years seven to eleven. That was a third of our lives, our whole adolescence more or less. We’d spent most of that time looking forward to getting out of the place.
In those days, before Neighbourhood-Comprehensives, the girls in our form nearly all took two buses in order to get to school so we were scattered all over the city. We rarely if ever just bumped into one another outside school hours. Not ten percent of us had phones at home. Mobiles and the internet were still in the realm of science fiction. In term-time we did make arrangements with one another to meet at weekends or in the holidays to go to Cliff Richard, Carry On or Elvis Presley films, the library, swimming baths, Beatle concerts etc and occasionally to one another's houses for tea, or one another’s churches, but when we left school none of us got around to doing anything in particular about meeting up again. I don't suppose it occurred to us that it would be necessary : we were the first-ever form in our school to go through a grammar school regime so there was nobody older to tell us. Everybody else in our year had left several terms earlier (Leaving age for Secondary Modern pupils was at the end of the term in which one was fifteen) and they all lived within walking distance of the school and one another.
Some of us were starting work the following Monday,some of us couldn't make any decisions until the O level results came out a month later when the staff would post them to us, and all in all in the excitement of our new lives it got forgotten. As an adult looking back I can see that we might have seen our reasons for doing things together at school and in our free time as being mostly for the purpose intended without noticing it could be simply because we were friends and liked one another's company.
When this cause of my loneliness - pure and simple loss - struck me I accepted it, had a good cry for all the girls, naming them one by one, - and to my surprise even some of the boys

- and then I was able to move on,make friends at work and my new church,get involved in other things,and generally realised that transitions are almost always painful but have to be gone through until life settles down again.
Somehow an expectation at the back of my mind of what friendship should be like must have been blocking my ability to make that transition.Once unblocked,it all got better and the loneliness melted away.During that period of loneliness I felt ashamed of it and never told anybody at work or at home about it. Seventeen-year-olds think oddly.
It wasn't long after I was over that stage that I also started hearing from classmates again, actually. I wonder now if they'd been feeling the same. Perhaps it was normal for that age-group in our situation in those days.
Over the years since then I've noticed that friendships do tend to flourish in context and sometimes when that context alters the level of friendship alters with it. There are only 24 hours in a day and many demands are made on our time.
I am sure the sort of thing I went through nearly fifty years ago can occur at any age when major change occurs,especially if it's unexpected or doesn't happen in the way one expects.I've seen proud new fathers,for example, turn into very unhappy men when their wives become so info-centric they don't know their husbands are even there.They miss the wife they had,the joy of expecting the planned-for baby and the anticipation of being a happy family man. Frasier Crane told his first phone-in caller, who'd had a broken engagement, she was in mourning for her life the way she thought it was going to be. He himself was badly disappointed at losing his intended freedom when his father was shot on duty,had to retire and move in with him. I think in real life that sort of grieving can be confused with loneliness,or perhaps when unrecognised be the cause of it.Isolation while in company can have a similar effect. Being with people where one is excluded from full participation,or where nobody else has the same views,values or intelligence is an example of this because it emphasises differences and makes one feel left out.
There are friendship fellowships for Christians in some towns, made up of single people who specifically want to socialise in groups with other believers. It might be worth your while findng out where the nearest one is if you don't belong to one already.Joining an interest group or a class only for the purpose of making friends there rather than for its own sake rarely works and is expensive.
edited to correct confusing punctuation typo.