I've recently noticed that I have some discharge coming from my anus, it is a yellowish colour and very strong smelling. When I go to the toilet and wipe myself there is nothing there but yet the discharge is on my underwear. Also I have missed a period, I know I'm not pregnant as I have been steralised and my husband has also had a vasectomy as we were informed there was a risk my tubes could fuse back together. Can you give me any indication as to what this may be please.