Any ideas on how to lose weight quickly? I seem to have hit a plateau. No matter what I do, can't seem to lose?

I have been overweight all my live. I was doing well for awhile. But I had a miscarriage in Dec. and since then my stress levels have been very high. I gained back about 15 lbs that I had lost and now no matter what I do I can't seem to lose the weight again. I can't just give up I am still about 80 lbs overweight. I have lost about fifty lbs in the last 2 years in between having a a baby but I still have more to go. Any ideas?