Bulimia Help

Many people think I have a serious issue with food and my therapist is the one that pointed out that many of my symptoms suggest bulimia. The problem is, I'm really not a classic bulimic. I can't throw-up. I've tried (for hours and until the back of my throat is almost raw) to make myself puke and I just can't do it. I stop myself as soon as I feel the vomit coming upwards. Now, maybe this is a blessing in disguise, but instead I wish I could just puke and be done with it (the food, the guilt, the stress). Instead I either take laxatives or exercise for hours (upwards of 3 hours on some days). Is it possible to really be purging if I'm just exercising? What if I just want to exercise after a normal meal, is that considered a purge? Sure I ran 3.5mi this morning in the snow, but I just had lunch and am looking forward to spending some time on the treadmill. It's so frustrating that I can't be successful at eating normally and I can't even be successful at being the perfect bulimic.