Help with Anemia

I have recently been diagnosed with iron deficiency anemia. Doc gave me high dose iron pills and I did not go to the bathroom for over a week. I stopped taking them and my stomach has not returned to normal, alternating between D and C and bloating. The bloating never goes away. I struggle with IBS-C to begin with but had it under control until I started the iron pills. Also, I gained a significant amount of weight since starting the pills and it has not went away since stopping them (over a week ago). Do iron pills make you gain weight? I'm so angry because I worked my butt off to lose it and now it's all back again in a matter of a week!!
I tried another product (Floradix) and same thing, messes with my stomach something fierce! I am afraid because I know I need to get my iron levels up but I seem to be overly sensitive to non-food iron supps.
Also, can anemia cause insomnia? My doctor said it doesn't but there is no other explanation. I either cannot fall asleep or I wake up 3-5x. I'm so exhausted from both the anemia as well as not sleeping that I feel like I just can't function. I have kept up my exercise the whole time and I count calories so I also don't know where the weight gain came from.
Please, please can somebody answer!