Anxiety dampening joy

Backstory, my first pregnancy I miscarried at 10 weeks. Second pregnancy I went into labor at 29 weeks and delivered my son at 31 weeks. He spent 5 weeks in the NICU. Several miscarriages after my son we did infertility treatment and IVF to get this pregnancy.

Now 27 weeks with my second son and instead of anxiety lessening I find myself unable to sleep stressing out. I thought reaching viability would help but so far it’s getting worse. Why can’t I calm the hell down and just enjoy the pregnancy I went through so much to get?