I got some horrible depression for a while after my divorce. Couldn't lift myself out of it. I went off for long walks over the hills regardless of the weather as often as I could and then after that mtb riding everywhere.
Just getting that buzz, natural high from physical exercise on a regular basis did it for me. I'd previously been down the medication route, it's just a quick fix. Whatever you do don't try to cheer yourself up with beer, it really mixes badly with depression.
Book yourself in on mtb holiday somewhere warm and friendly I'd say, give yourself something to look forward to. 🙂