I had it too with my first. Be aware the iron pills cam cauae constipation as it did me. I ended taking one instead of the two prescribed and did just fine and was able to poop lol.
I had this with my first pregnancy and it didn't pop up until a little later in my pregnancy...I want to say around 29-30 weeks. All they did was put me on several extra iron supplements per day and then do extra blood work the rest of my pregnancy to make sure my levels stayed up. You'll be fine!