Mrinda, without more info it's tough to give a good answer, but I think the big clue is losing weight. I'm with Davis. If you're losing weight and getting weaker, you need more food. You also need to get at least 7 hours of sleep a night, although 8 is better. Get lots of carbs for dinner the day before your session, then lots of carbs right after training, and kick your overall intake up closer to 4k.
Current PRs at 242- 495, 335, 565, 1395