My fish is getting bigger then smaller then big again *Like in the belly*?

Ok, so I went to a lake and I got a little guppy, I thought that it was goning to lay eggs because her belly was huge! I git her home put her in a nice big fish bowl and was feeding her betta food. About 3 weeks after I got her in the tank, she got this fish sickness called ick. I put meds in the bowl and I knew that the meds would kill the eggs if any inside her. But I wanted her to get better so I put it in there. Then 2 weeks after changing the water, regular feeding and normal behavers, she got small. I knew that if there had been any eggs in her she woul have already disposed of them in her wast product. at least 4 weeks after that (That is now) she is big again! I have no idea if she is going to lay eggs, I have strange vision, or she has a wait problem! Please! Tell me what is up with her/him!!!!