Can I run when I am pregnant?

Once a day, after meals — whenever my roommate isn't around, I stick my fingers down my throat and throw up most of the food that I had just eaten. I do not binge — I only purge. I understand from my Psychology professor that the diagnosis of bulimia nervosa requires that the person binge and then purge. I am curious, then, what I have — do I have a form of anorexia nervosa or what? Also, I am on birth control pills and I am afraid that I might hurt their effect by throwing up. How long does it take for the pill to get absorbed into my system? I usually don't throw up until about 5 or six hours after I have taken the pill. Will this hurt the effect of the pill?

I have recently started to stretch to start learning yoga and I have become sore in my muscles, and was wondering if I am sore the next day after stretching, is it okay to stretch the next day when I am still sore?

1) When I do a 3-mile or 5-mile run, I run for time and try to finish with nothing in the tank. The closer I get to the end, the more I push myself, because I know I don't need to sustain the effort much longer. When I stop running, I suddenly get very light-headed and dizzy. It never happens while I'm running. I walk briskly while I'm warming down, but that doesn't prevent it. Why does this happen? Is it dangerous?

2)  Sometimes after jogging a while, or cycling a great distance, my head begins to spin and I feel as if I'm going to pass out. Is it normal to have feelings like these, and if so, how intense should these feelings be?

Are there other types of eating disorders other than anorexia and bulimia? For example, I have this fear of unnecessary fat in food and eat everything "plain," that is, without butter, oil, dressing, or sauce, etc. I thought that it's good that I'm this health conscious, but my friends say that it's a little obsessive. Is this an eating disorder?

It's been about three months since I worked out regularly. I find that lifting for strength (i.e. 80% of max for 5-8 reps) causes me to feel nauseated about 3/4 through the workout sometimes, so that I can't bring myself to finish. I took a weight training course last semester and was affected the same way every once in a while. I warm up, stretch before and after, breath when I lift, drink plenty of water, take care not to eat 1 hour before working out, skip a day between workouts, don't lift more than I can handle (I reduced the weight from what I ended on in the class to a seemingly suitable weight. I got a 98 in the class incidentally). What's going on?

My trainer is getting annoyed because I am not experiencing soreness. I have been working out now with him and other trainers, three times a week, for three months now. Plus I do 45 minutes of cardio four times a week.

I think it's kind of odd that he bases his progress on how sore his clients are. I was always led to believe that soreness in muscles comes from working newfound muscle groups or aggressive workouts. During our workout I am feeling my muscles being worked and I have lost a number of inches and lbs since I have been working out. It seems to be a large issue with some of the trainers at this gym. I am wondering why! Also he had me doing 420 lbs on my legs. I am not a body builder nor do I want to be. I started to tone up. Advise please!