I’ve had a fair share of colonics earlier on. I do remember that it took me a long time to get back to normal with my gut afterwards. My biggest problem was that I lost my bowel movements and had to re-train myself to go by myself again (though they claim that colonics are supposed to help with that). I also remember sometimes having some bloating afterwards as if my gut was just irritated. I also had problems with gas but never really thought it might have been caused by the colonic (though it is possible).
You will need to rebuild the gutflora by taking high strength probiotics. These may also cause gas and bloating to begin with, but this should not last a long time. You may also want to take some prebiotics (i.e. FOS) to feed the good bacteria in the gut. The colonic lady should have told you about all of this.