I've a few things which aren't great:
- me and partner not getting on for months
You do still have a partner. It would be easier to patch things up than deal with a breakup, so spend some time together.
- I work with a small team and don't really like most of them. In fact I can't stand 2 of the 6 people I work with.
You like the majority of them. Who cares about the other 2? There will always be people you don't like at work.
- my work involves being in a windowless office for 8 hours. This means there's no natural light. It's horrible and it really gets me down and I feel trapped.
Sunlight in the winter (in UK) doesn't provide enough Vitamin D, so even if you had natural light you wouldn't technically be getting enough.. try changing your diet or taking vitamin pills to supplement the lack of Vitamin D. (link)
- bit depressed and not overly happy.
Stop drinking "just because". Go to the movies or go for food with your partner... alcohol is a depressant, so it's only making you feel worse