I am sick with colon. I did my 'Umrah, and during Tawaaf around Ka'bah, I felled some gazes going from stomach, but I am not sure it is going, what to do? I repeat my 'Umrah again?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.

Your 'Umrah is valid, Inshaa Allaah, and you are not required to do anything because you were in doubt whether or not your ablution was invalidated. The Islaamic ruling is that certainty cannot be overruled by doubt. As long as you had ablution and then doubted whilst circumambulating around the Ka'bah that some gases might have come out of you but were not sure, then you are not required to do anything. It is reported by Al-Bukhari and Muslim that 'Abbaad Ibn Tameem told the Prophet about a man who suspected that he passed some gases during prayer, and the Prophet told him: "One should not leave his prayer until he hears a sound or finds a smell." The narration of Abu Hurayrah reads: "If one feels something in his stomach and doubts whether or not he passed some gas or not, he should not leave the Mosque till he hears a sound (of passing wind) or finds a smell (of passed gas)." [Muslim]

Allaah knows best.