Hi! I just finished my 30 days on the dewormer. I am also 5'4 and am a very thin 110 pounds. I am VERY small boned so it makes me look even more thin than I am - I now wear a size 0-2, down from 120 pounds and a size 6 that I was before doing all this cleansing.
I had no problem taking the one tablespoon twice daily. In the beginning, I would feel a bit of nausea when I first took the dewormer, but that soon passed. I never felt sick or felt that I was suffering from an overdose. If you are worried about it, take a little less than a tablespoon. If you feel okay, then work up to a full tablespoon. But I don't think a full tablespoon will bother you. My 195 pound husband was taking the same dosage that I was and he was expelling a lot of worms. I was taking this same dosage and expelled no worms and suffered no ill effects.