ugh! so sorry to hear it!
my favorite go to food for constipation (and in general) are bananas. Prune juice is also good. and I think oatmeal.

yeah, avoiding the foods you mentioned should help.

if it's IBS, stick with the BRAT diet for a while. Bananas Rice Applesauce and Toast. Or BRATTY which adds green tea and yogurt. I think yogurt might need to be avoided if constipated though, or limited. It works better for diarrhea.