Pre-existing trouble with Depression - and being pregnant

Hello ladies! I haven't been very active on here at all, but am feeling the need now to ask for advice / discuss what's going on in my pregnancy journey. Hopefully getting things out will help and if anyone has advice or experience with the same thing I'd love to hear from you too. 

I've had depression for years after a crazy and difficult childhood and in January 2015 started on a pretty bad series of episodes - a lot of feeling very blue and disinterested in everything, not being able to handle things, getting very emotional, tired etc. I was managing things OK until I got pregnant and had to go off one of my medications (one of the few that was working, too!). After a few surprisingly good months in the first trimester the second has brought on some pretty familiar symptoms and as I enter the third trimester next week I'm still feeling really down and sad. My DH and I want this baby very much, and I'm excited to start our family, but at the same time the depression is crushing me. I want to enjoy being pregnant and being a young mum, but feeling so rotten is sucking all the joy out of things. My midwife and the doctors I've seen are doing all they can, but so far it hasn't shifted the clouds enough to make much of a difference. I'm doing the stuff they say and trying to stay active and involved with friends and such, but it exhausts me and I feel like nothing is ever going to change, in fact, it'll probably even get worse after baby arrives... 

I don't want to ask for a bunch of sympathy from you lovely ladies, or find a miracle cure or anything. I'm well aware its likely to be long-term and will probably always be part of my life, but I think I just need to know that it isn't only me having a hard time with this. I'd love to hear from mums who've made it through, or who are also having a hard time, as I feel so alone and crushed these days... Anyway, sorry for springing up on the the boards like this and I hope I'm not the only one who isn't having a blissful pregnancy (I mean, I wish all of you were, but I highly doubt it).