Difficult day

So a couple days ago I found out I likely have polyhydramnios and baby might need to come early or I might have to have an amnioreduction procedure (or both). Today I found out I'm anemic from the blood they took Monday. I know anemia is really common in pregnancy but I can't help but wonder how long it's been going on - I haven't had blood drawn since about 9w (I'm 29 w now). 
Also I can't help but think of all the things that could be causing the excess amniotic fluid - I don't have gestational diabetes but there are several other things that could be wrong with the baby that could be causing it. 
They are doing an ultrasound on 8/29 to assess how to move forward. 
I'm having a hard time staying positive - I keep thinking that I'm failing the baby. I weigh 230lb and I've gained 30 during the pregnancy. Having a lot of guilt about that too.