32+ weeks pregnant, what could this be ?

for the past 3 days or so i've had a sick stomach, & yesterday evening i got lightheaded really bad & nauseous. I woke up in the middle of the night @ 3 am to pee, since then i couldn't fall asleep, my baby has been moving of course, but his movements are pretty hard and sharp time to time. I've had mushy stool a darkish green color. Yes, i do take iron supplements, but i've been taking them for about a month now so i'm not sure if thats the problem, because this has only took place with in the past 3/4 days. My belly felt tight for about 10 minutes this morning on & off.... what does this mean !?? I don't feel like running into labor & delivery for every little thing that i feel is "wrong" , they're probably getting tired of me lol. I've been there about 4 times since i got pregnant.