I know what your feeling, it sucks. I was 32 when my afp came back abnormal, yes a very high false positive rate. My feeling is they shouldn't even use it.
Amnio was not bad (limited pain) the needle is large and you feel pressure, but not a lot of pain. It hurts when it first goes in, then you feel pressure and then nothing.
They do have a test that they can do along with the amnio that is 98% I think it's called a FISH test, ask about it. You get the results back in 3 days. Amnio can take 2 weeks.
I wish you all the best.
Daughter 5, UC
Pentasa 2X2 daily
Folic Acid 1000mcg.