That means your tummy fat never disappeared. When you eat, your stomach actually fills up with food…so it will expand LP! 
The only way to get rid of tummy fat is crunches…you have to work your abdominal muscles to burn the fat off of them.
Thats not heavy enough hareem dear. Try at least 2 liter pop bottles. OR go and buy yourself two sets of dumb bells…one light and one heavy.
BBC…you’ve gotta do a little more. Picture the fat on your belly (if there is any) and picture the muscles under it trying to get out. The harder they work, the thinner that fat layer gets. Crunches are a great way to start. They will be hard and you dont have to start by doing 500 of them! Start by doing three sets of 25. There are also several different types of crunches you can do.
This looks hard but isnt really that difficult…takes more courage than strength:
If you’re not burning, you’re not working…just getting tired. Increase the weight and repititions.
OH and please try any exercise for at least 3 weeks before expecting any changes!!!