I Was On A Steroid About For 7 Days 4

I was on a steroid about for 7 days 4 weeks ago. The past week I seem to be gaining a pound a day. I don't usually fluctuate weight like this and have not had a steroid before in the past. I hear it could be from the steroid but would it have happened before now? I am a tennis coach and hike or walk every day. I am very active and eat fairly healthy. If this is from the steroid when will my own metabolism take back over and I can get back to my "normal'' weight.