Suicidal mom

I've been dealing with what I'm not realizing is really bad PPD and it seems to be getting worse instead of better even though my son is a year and a half. I feel so low that suicide is the only escape for me. I want so desperately to be happy with my life but I can't and I just want a break. I'm beyond scared to seek help because I don't want my son taken away from me and that's what the healthcare system does. I'm at a loss as what to do, I think I should just leave my son with my husband and his family and leave but the only way I could do that is to kill myself. I really think my son would be better off with another woman being his mom. My husband wouldn't care, his family would be beyond happy to raise my son and I honestly believe my son would be happier without me.