26 yr old. had constip. went semi normal after fiber and stool softener. now diahrea. could diet change and softeners be the cause? scared.

Yes.: Pretty common for someone with constipation to overshoot and cause diarrhea. Back off meds and eat regularly. If this recurs consider seeing doc.

Sounds: Like you went to the other extreme. Stop laxatives and softeners and eat a high fiber diet and drink 80-100 oz caffeine free alcohol free fluid daily. If still having issues see a GI doctor or colo rectal surgeon.

Sure: Too much of a good thing. First cut out stool softener. Balance and consistency of input will help consistency of output. Ongoing symptoms? See doc to exclude other issues.