extreme exercise and low iron

I've been training with a personal trainer for the past 3 weeks and my sessions are getting a little more intense and we are starting to push my body a little harder which is great until yesterday once we got into our workout I started feeling light headed and got really dizzy, we stopped our session & I went home to hydrate and relax. This morning I woke up still light headed and dizzy, so I made an appointment with the doctor. My question is since surgery I've had extremely low Iron levels, I take medication and I've had to have two blood transfusions, could my intense workouts be effecting my iron levels even more, could that be the reason I've been feeling light headed and dizzy? I drink about 2.5 to 3 liters of water a day and I always have extra water around and during workouts, as well as a pre workout protein shake and a healthy carb snack.

I'm not a doctor by any means but just from what grade 11 or 12 biology would tell me, I think intense exercise DOES affect your iron levels. Heart rate increases, blood travels faster through your body, hemoglobins binding/unbinding iron faster, correct? Definitely ask your doctor though, and maybe until he/she gives you the "all-clear", take it a little easier.

I think you should make an appointment with your doctor so you can set some safe boundaries for yourself.