I cannot suggest anything here, I can just give you my own experience and perception of me when I had mine.

I currently suffer with depression but have not always, so I have a pretty good gauge.

Depression and postpartum are similar to me. It's like the worst ever pms (like times 1000) without any of the good stuff. It started in general after 2 weeks.

I thought bad things when I had my babies (I didn't have the resources I do now). I was ashamed to tell anyone how bad they were. This is the thing....I reconcile it this way (after much though and self-therapizing....): To me, thinking them was my way of dealing with them without having them happen...like thinking the worst case scenarios (and I didn't WANT to think them, it just happened) anyway, by thinking them I was mentally preparing myself. And that's all.

For a little additional understanding that you may or may not find useful, I also seem to go through tragic incidents in my mind...I have deeply grieved the death of my mom even though she is not dead...I am not sure that others do this, but my brain does. Maybe this behavior needs outside assistance, but I know why I'm doing it. It's way to prep myself (It sucks but it is what it is)

So...I did the same thing with my own babies..not the grief, but other instances. Things that the odds of happening were astronomical. Things I might do. Things that might happen.

I don't know if that's the experience of other moms with postpartum. I cried a whole lot. I felt lonely. I couldn't bring myself to go out or get help. Mostly people thought I was okay.
Back then, that's what you did.
But nobody in history ever, ever loved anybody as much as I did my babies. Just like you do.

I urge you to get help and not wait too long.

And (just food for thought) I stayed home with mine. My sister went back to work at three weeks. Both were right for each of us.

I promise that you will not always feel the way you do now. But you don't have to suffer like I did during what could be the most joyful time of your life. That would be tragic when help is available.

Hugs.