Hello,
I'm coming back to this site after having my first in September 2017--loved having the support here! I have struggled with anxiety and depression most of my life as well, and wanted to add to FLArmyWife's response. I have felt the same way at times. My anxiety and depression were fairly well managed before getting pregnant, and pregnancy was AMAZING. I don't know if it was the hormones or the fact that I was doing something way bigger than myself, or a combination, but I had very few problems during pregnancy. After my son was born, though, we struggled. I had dark days frequently, where I didn't want to do anything, I had the nightmarish visions that FLArmyWife talked about, wanting to harm myself or my son, and my relationship with my husband deteriorated. All I did was nag and yell at him. It didn't help that we slept in separate beds for the first 5 months of my son's life. I would also frequently regret having our son, since it made everything so complicated. This all continued for about 16 months after having our son.
Two things changed at that point: (1) I started a higher dose of my antidepressant, and (2) my husband and I figured out our issues. I had to double my antidepressant dose to get the same effects as before, but it helped. However, my relationship with my husband was key. It took some major patience and hardship to finally figure out what was the problem with our relationship. It ended up being score-keeping (with our son and with house responsibilities) and not enough demonstrations of love. He thought I didn't love him and I thought he didn't love me. We recommitted to our relationship, talked through each one of our spats to figure out a solution, and made time to be physically close. Mind you, it's still not a perfect relationship by far, but just having the knowledge that he supports me and I support him, even when we are angry, is huge. We also started chore lists, a weekly menu, and a to-do chart for the week, so we couldn't be surprised when someone is late from work one day or has to do something the other didn't anticipate.
I still find myself depressed sometimes, for 2-3 days in a row, my anxiety isn't great, and I lose my temper a lot with my son, but it's a hell of a lot better than it was. Our son is 2 now, and can express himself when he is frustrated, so that's been helpful too, even if he does have temper tantrums all the time... I love him with all my heart and don't regret having him any more. He can make me laugh so easily, and his hugs and giggles are seriously the best. If I could have a do-over, I would probably wait another couple years to have him (and take a few more exotic vacations...), but I wouldn't choose to not have him, like I did when he was younger.
So the moral of my story is to have a support system. If you have a therapist and a supportive partner who will stick with you through your lowest points, and maybe some family and friends who will be able to watch your baby when you need a break, then make your dream come true! Also, most doctors don't hesitate to keep women on antidepressants during pregnancy, but if you don't want that, consider seeking out a homeopathic remedy. I'm seeing a naturopathic doctor to prep for my second pregnancy (hopefully early 2020), and she has prescribed a bunch of vitamins for mood plus a homeopathic remedy. I've only been on it for a few days, so I don't know the ultimate result, but it's certainly worth a try since it's totally safe during pregnancy!