This is going to sound dumb but just get out of your house and wander around the area you live in. Find a park or a cemetery to walk around. Sit on a bench downtown and people watch or just fuck around on your phone somewhere that isn't your bed. Hang out in the library and read or use their computers instead of sitting in your room going online in private. Look for stores and cafes that don't mind if you sit for a long time without spending money (niche hobby stores like bookstores and game/card and comic shops are good for that. Low end chain cafes like Dunkin don't pay their employees enough to care if you sit in the corner without buying stuff). If you live somewhere with public transport ride it around your town just to waste time looking out the windows. If there's sidewalks or bike paths, start a walking habit and get to know the streets and buildings around your home. I started forcing myself to do this kind of stuff when I was recovering from a really severe shut in agoraphobia/depression episode after I lost my job, and it was a good way to gently ease myself back into society. Start slow, once or twice a week, hell even once or twice a month if that's all you can manage, but the sooner you start to build the habit of going out the better.
Also, you mentioned that you do have friends but you don't feel like you fit in with them. Already having friends is a huge advantage here, even if you're not as close as you'd like to be. Locking yourself away from them won't help that. Invite them to game with you on the weekends. If they mention a hobby or interest you don't already share, ask them to explain it to you. Tell them that you're bored and looking for opportunities to do more. Even if you do all of this and still don't connect, don't look at it as a waste of time and energy. This will be good practice for communicating when you find people you actually DO have things in common with. Your social skills will be sharper than if you do nothing now and just let those potential connections die on the vine while you sit in your room letting your social skills atrophy even further. I made that mistake and I regret it so deeply I'm on this forum. Don't be me.
