URGH!!! How horrible of your IL's to say those things about you!!!!

DP and I are not married, and we had only been together for 7 months when I fell PG last year (I was 20 and he was 21). We had a few fallouts with MIL as well... She even suggested to DP that he should get our baby DNA tested just to make sure it was his (GRRRRRRRR!!!!!) and all sorts of other nasty things about me.
But in the end I forgave her, and now she is a doting granmother and absolutely adores Aidyn.

I think for the time being you should stick with those ppl that are supporting you and leave it up to the IL's to try and mend the damage and hurt that they have caused.