Pregnant and depressed

Oh man am I struggling. I've suffered with depression on/off for the best part of 15 years. I currently see a therapist and I'm 32 weeks pregnant. My depression comes from attachment issues from growing up, and my self esteem is rock bottom. I just can't shrug the feeling that my husband and unborn baby would be better off if I wasn't around. I feel so guilty that this baby is going to have me as a Mum. I wanted so badly to give my baby better than I had, but how can I when I can't fix myself? I've been to therapy for years and I've been on meds before...it all helps in the short term but ultimately you can't change who you are. And who I am is no good. Not for my husband and not for my baby. I feel so trapped; If I wasn't pregnant I'd end it but I can't do that to this baby. So tonight I've made a plan. I'll have the baby and pretend like everything is fine. I'll give my baby the best I am capable of for 6 months Then, before my baby gets old enough to remember me, and when it starts to get hard to keep up the charade for longer, I'm gonna take my life. I'll spare my baby having memories and a lifetime of a crap Mum. It's the best I can do for him/her.