i'm starting to lose too much weight!

ok i know this a weird problem and not the norm but what can i do to gain weight on my top half?  i had my lap rny almost a year ago and have lost 137 lbs!  i try to take in 1800 calories a day but i do circuit training 3 or 4x a week for an hour a piece and 3x a week i walk 9 miles...my bottom half is ok but i look emaciated on the top!  not to mention i'm looking kind of gaunt in the face....i take tons of supplements and eat every 3 hours and get my protein in and feel healthy as a horse....i don't want to cut down on my exercise because frankly./..it makes me happy and i'm very prone to depression and had been on antidepressants for years...any suggestions?

I workout at my gym with a girl that has a large rump.  I have never seen anyone as in-shape as she is but she's just got a lot there.  She told me once that when she ran a marathon a few years ago that she lost enough weight that her butt was finally where she wanted it to be.  Unfortunately her upper body was (like yours) too thin.  There was nothing she could do about it.  When she put enough weight on to gain on the top her butt got big again.  That was just the way she was shapped.  I am not sure if weight training would address what you are talking about or not but I think that it's probably your only possible solution if you don't want to change your lower body.