Hobbies can definitely help. What do you think of pottery? I joined a group last year and it is the loveliest friendliest group. It can take a while to get on a waiting list, but be patient. There are so many different techniques to pottery, some more technical (the wheel), some more creative (sculpting) and lots in between.
Also, do you have any plans to have children (sorry to ask such an intrusive question), but for me, as soon as I got pregnant and joined the NCT I made lifelong friends akin to my uni and school friends. Once mine started school I suddenly had loads of really great amazing friends and a great social life. By contrast my 20s and early 30s were quite lonely.
Obviously you shouldn't have children to cure loneliness and not everyone is fortunate enough to be able to. But if you do have them, you will most likely end up with lots of friends.
If you don't want or aren't able to have children (I have lots of friends that don't and lead wonderful lives), then you need to be a bit more proactive by joining things and being persistent. These things take time. You could always post something on your local community Facebook page asking if anyone fancied a coffee and chat group at a local cafe, or in a pub. I also set up my own group when I had my second baby and it was really successful. There will be plenty of others like yourself feeling exactly the same. I would also plan weekends in advance and see if you can book weekends away with some of your old friends. I would also make the most of this time to travel.
It is hard, but once you start being proactive and persistent, it does pay off. And also your confidence will grow. That has definitely happened with me. I used to be so shy, but now I will talk to everyone and organise street parties so that others aren't lonely on our street.
It's honestly so common to be lonely, but I guarantee you that there will be people your age living on your street or around the corner who feel exactly the same!