Dieting dilemma

So I went 5 weeks straight eating around 1200 calories a day. The first week I lost 4 pound and felt so encouraged. Then next week I gain a pound, don't know how or why. After that I continued to gain a pound a week until I found all 4 pounds I had lost. The frustration and caused me to back slide and give up counting. Yet not counting my calories and not exercising I haven't gained anymore then the 4 pounds I had lost and refound. It is so frustrating and I just don't think there is anyone out there who can fully understand what this is like for me. I watch all my skinny family members eat what ever they want and not or have health issues. Yet I smell what they eat and I gain and/or my BP goes up.  This really sucks. I blame myself. I think I am doing something wrong subconsciously.
Today I started the day off eating the wrong stuff. I ate pancakes and had 2 cups of coffee. I like to limit my coffee to 1 cup due to the 50 calories I like to add to it. I really wish I enjoyed black coffee.  But to make up  for my eating failures I did some stretches and a small arm work out. I need to exercise. My BP was high at my dr. appointment this week. But I am having fatigue issues and so my work outs need to be short and not to strenuous.
Here's to hoping.