Hi LWCericato,

Sorry you're feeling so bad. This is a very good place to come for support, so keep posting. Sometimes it takes a few posts before you find someone who shares some of your experiences.
Depression usually makes things look and feel worse than they would otherwise. It may be worth apologising to your girlfriend and trying to show her you're sorry and want to be friends again. You know her best.
Depression often robs people of friends as we don't feel like socialising.
Is there any one of your friends that you could reach out to and start to see them again?
One of them may be more open than the others, especially if you explain that you haven't been well. No need to say what the illness is, just have an explanation ready.
In the mean time, keep posting here, there are people who will understand.

I had a slow start here, but now I get a lot of support from different people. I really hope you get the support you need here until you are more confident and can make or renew more friendships.

By the way, good English!