Frustration over weight gain

I'm a 5'3", 37 yr old female who has been on medifast, a ketogenic diet, until this past January. I started at 165lbs last May and had gotten down to 151, but bounced back up to around 153. When I started this program, I was doing a lot of walking, mostly speedwalking, but started doing a lot more running last fall. I was also doing more HIIT work on the treadmill doing sprints. I was told by my counselor on the medifast diet, that I was not eating enough calories (~1000 cal/day) and with the moderate exercise that I was doing, I wasn't eating enough. I increased by about 200 cal/day but had started to gain weight. At that time, I found out I was pregnant and came off of the medifast plan to avoid ketosis during pregnancy. I started my fitness pal again and decreased my exercise to just speedwalking (~9-12miles/wk). I ended up having a miscarriage ~10wks and began trying to lose weigh again with my fitness pal. I started running (trying to work up to 10mi run) and continuing my speedwalking. My goal was to lose 1lb/week and so my diary suggested 1390cal/day. I religiously counted my calories and bought a food scale. I average ~15-20miles/week running and ~4miles/week walking. I have started to gain weight and inches and so I changed my goals to losing 2lbs/week, which dropped my calories down to 1200cal/day. I have been eating calories back when I exercise to avoid eating too little for my activity on any particular day, but I don't tend to go over the allotted amount. I drink more than 64oz of water per day. I'm very frustrated as I'd like to see results after all of my hardwork. I don't understand why I'm gaining weight and inches at 1200cal/day despite my exercise. With all of this, why am I gaining and not at the very least just maintaining? How can I get this situation turned around?