Torn pls help!

I’m sure I’ll receive a ton of backlash for even asking this here but I need someone to vent to....

SO and I have been married almost 10 yrs. He has a 13 yo from a previous marriage and then we have 3 more of our own. Youngest is 10 m. I just found out I’m pregnant AGAIN! We did not want another baby. And in fact after we had unprotected sex in Dec I took a plan B pill just to be on the safe side (first time ever doing that and that was horribly painful). So when my period didn’t come around New Years I knew something was up. Sure enough I was pregnant. LMP puts me 9&5 but US has be measuring 6 days behind that.

We have not told a single soul I am pregnant (except my doc) and I am seriously considering abortion. I suffered terribly after my last pregnancy from PPD. It was very scary and I don’t like who I am when that happened. I don’t get help from anyone in family and my husband works 40-70hr work weeks. I am always alone and outnumbered. My appt is scheduled Thursday this week. I have never had an abortion before, in fact, I’ve actually had two miscarriages in the past and those were so traumatic. Idk if I can go they with it but idk if I can honestly deal with another newborn and four other kids on top all alone again.