bummed...need some advice from all you informed cc-ers!

So, a little background.  I'm 5'4 and 135 (+ or - a few) lbs.  This past year, I have had some stomach issues (lack of appetite, stomach aches, etc) and lost about 10 pounds over 3 or 4 months and have been maintaining that weight for about 4 or 5 months.  I wasn't eating a lot for about 3 months and also have been really dedicated to working out like 5 or 6 times per week.  I've always been active though, just upped the amount of cardio and weights I was doing.  Nothing crazy or anything.

So I've gone from 145 to about 135lbs.  After reading lots of posts and putting my info into the calculators on this site, I realize that I can eat more and maintain.  Problem is - I have been eating more (and working out a little less, maybe 4 or 5 times per week for a shorter amount of time) but I have been gaining weight!  I'm still active, so I thought if I upped my cals, it would actually be better for my body.  I eat every 3ish hours....really healthy too.  My stomach can't handle dairy, fried foods, foods high in fat, etc so for snacks I eat fruit and veggies or some dry cereal.  I eat salads or turkey sandwiches or veggie sushi for lunches.  Oatmeal/cereal for breakfast. 

My questions: what do you think my cal intake should be??  I eat about 1800 or so cals per day and you'd think I could still maintain but I am beginning to slowly gain.  I do about an hour to 1.5 hours of exercise every other day or so.  What gives???  Do I need to starve myself to actually lose weight like I was doing before (b/c of my stomach, not ED)?  I'm a little discouraged and would appreciate any help/advice!

Thanks :)

The usual reason for gaining weight is that you're eating too much. 1800 should be OK for maintenance but you need to measure that quite carefully and not guess.  Keep your food diary accurately for a couple of weeks, weigh & measure the portions and see if you're eating more than you think.

Another thing to factor in is that you lost 10lbs essentially by starving due to ill health.  When bodies lose weight quickly because they are under stress the natural recovery response is to regain the lost weight quickly.  So you need to be patient, allow your body to get used to 'normal' food intake (1800-2000 cals) and let things settle before getting anxious about any gain.  Give it 2 - 3 weeks.