Help with weightloss while pregnant?

Victorian

I am 5 weeks and was planning a work out regimen before I found out I was pregnant. I know I need to be healthy enough for my baby but i also don't want to get huge in the process of this. Anyone have any work out regimens, dietary suggestions, or just general advice on how I can accomplish this? I currently (last i check before i found out i was pregnant) weigh 161 and I am 5'5". Help please! I really don't want to feel like a walking whale!