Tilly and others who are depressed or dipping your toes into depression - it is such a hard place to be and I am sending you love. I've been there more than once and know that depression can be a kind of temptation - this sounds strange, but in my experience it is like wrapping yourself in a big, grey, sad duvet. It kind of numbs you from the world and gives a false 'protection' from it all - it feels like too much to get on with life, and is a place to hide. I don't want to sound unkind - I am saying what I realised about myself. So I found out that I have to pay attention to the depressing thoughts I am only half attending to, and ask myself if they are true. Almost always they are not - or I am giving an unnecessary negative spin to them. Reality is different - I was in a very painful marriage, but came to realise that that pain was not the same as the depression I was experiencing. I could move on from the depression, by lots of things including challenging my thoughts and by stopping crying so much. Also know that it is OK to feel whatever you feel - this is how it is for us all - it is the thoughts and stories which keep us stuck, so check them out and let them go, but allow the feelings to run their course - in the end you will 'digest' them. If and when they return, just follow what you've learnt, and move on again. And again. Don't blame yourself - self blame is just another way to pull ourselves down. What I found hard was to ask for help - easier to ask when you are feeling better, paradoxically. It does help to get out of doors and walk - if possible somewhere natural and beautiful, but walk anyway. Walk even if you think you are too tired. Exercise has been shown to be as good as tablets for mild or moderate depresssion, and doesn't have the side effects of medication.
And find a counsellor, or talk to a friend, or help someone else: do whatever you can to take that first step away from the duvet of depression. It won't always be like this. I wish you well.