I suffer bad constipation but am used to that now but the thing is every time I feel the need to go the loo for a number2 I get weird nausea just b4band sometimes after....

Is this even normal for ibs?? It does happen to me every time I need the loo just makes me worry as I have a phobia of vomitingb(not that I vomit) its just the nausea I hate