When I stand and walk, it feels as if I sat in water. There isn't anything to be seen. Wondering if it has to do with a colonoscopy I just had last week. Perhaps nerves were irritated? Should I check with my primary doctor or the gastroenterologist about this?

I think that sensation will dissipate. Of course that procedure will cause some unusual sensations for a couple of days. If it makes you more comfortable, see your doctor for a minor check up.