Why can’t I cheer myself up?

I’ve been really lonely recently, all my friends left for university around six months ago whereas I’m on a gap year. During this time i’ve gone through my first breakup and didn’t have any friends around me to help me through it. I’m still hurting and I’m frustrated that I haven’t moved on almost five months later. I have a couple of good friends near me now, and I’ve had some amazing news that I’ve been accepted into uni for next year, but nothing seems to be cheering me up. I feel ungrateful because nothing seems good enough to get me out of that low kind of state. Does anyone have any tips or experience with something like this?