I'm 26, height 5'3" and weigh 185lbs. I know, it's sickening. I need help.?

Here's the thing. I do not kid you ... I eat VERY little. When I eat a meal, I get SO full SO fast that I never finish my food. I snack occasionally, but nothing like one would think if they looked at me. I do, however, drink Dr. Pepper and a frequent Starbucks drink. I also have been battling low blood sugar. I honestly believe that this is my problem. Not to mention my prior lack of activity. I have recently been using Tony Little's Gazelle Glider and have been doing crunches every other night. I've done this for 2 weeks and lost 3 pounds. Then, I woke up this morning and had gained 5! I want to cry. HELP!! I need smart motivation. I can outsmart any phony little tip and I make myself miserable. I don't need smart alec answers, just people that truly care and have been there. Thanks.