Stopped excercising for 3 days and put on loads of weight!! WHY?

so im on my period and have been feeling fatigued so i haven't excercised for a bit. But my tummy has got enormous and i am like 2kgs heavier, from like 2 days. And im worried cause on the weekend i ate a fair bit of junkfood, and have been eating a lot for three days, no more junkfood but still a lot. And i thought it was bloating, but due to no pain or discomfort im confused. So have i put on weight, like fat??