Why do I feel like I'm 300ils and breathless?

I'm 40 pounds overweight and I thought I was doing good excercising and losing weight. I excercised almost everyday for a month. I started to feel inches off my waist. The problem is that my pants that were one size stretched with my weight and actually became my original size now. I was upset because I went to buy pants and I was convinced I had lost one or two sizes. That wasn't the case and I got discouraged for almost two weeks. Before I used to eat every 3 hours 6 times a day. I did 3 meals bf, lunch and dinner and 3 times snack. My snacks became bigger and this is where I started to gain weight. I also began not to watch what I ate, Now I have changed my diet again and to 3 meals a day small snacks when I get the craving which is like 1 or sometimes two times a day and sometime none. I have just made sure they are small portions. Anyways I had stopped excercising and today when I started I got tired quick. Before this during the whole month I was going turbo. Is this common when you stop excercising for some weeks to become tired quick. Is it because I'm at the obese level?
Why do I feel like I'm 300ils and breathless?
Post Opinion