eat more lose more

bakergirl178

okay so i've been eating at a net of 1350 since like september and i lost 6 lbs.. then i hit a plateau. over the weekend i was up in the mountains and i was eating everything i wanted, netting like 1500-1800 daily. but when i came down after 3 days, i had lost 3 lbs. i went back on the net 1350 and gained 2 back. is this water weight or am i not eating enough to support my activity level? i'm 18 and i am in track and field so i weight lift 2x a week and practice some type of aerobic exercise 5+ days a week.