I've not stopped going so don't worry, just make sure you don't do ab exercises and keep you HR below 140 if you can. You also need to rest for 2 minutes every 10 mins and drink double the amount of water. I've been seeing a personal trainer once a month just to check what I'm doing and get new exercises etc. I felt a lot worse, hotter and more tired at the gym in tri 1 than both 2 and 3 so far, so just remember to take it easy and stop if your dizzy. My tummy was also bloated for a few weeks.