From reading through many posts here, the medical literature and my own experience, one thing to keep in the back of your mind is that mucosal prolapse can occur at any point, and it can make evacuation difficult. Tall thin people with less abdominal wall fat are more prone to it. It's also referred to as "floppy pouch" in some literature.
This is not something caused by straining, but it will actually make evacuation harder if you have mucosal prolapse. Basically straining pushes mucosal tissue slightly, which "flops" around enough to tighten the anal opening so you can only pass liquid or strain to pass thin bits of formed stool.
If the problem persists it would be something to check out. There's a very simple (from patient's perspective) banding procedure to address it, but few endoscopists perform it. My condition was suspected based on clinical picture, diagnosed during a pouchoscopy and confirmed with barium defecogram and anorectal mammography. Banding by Dr. Bo Shen at Columbia improved things for me. Some folks have to have the banding periodically if the prolapse symptoms recur. For me, if it's needed, further banding would be done along with my regular screening pouchoscopy.
It's not the worst problem to deal with, but hoping your symptoms pass and you won't have to think about it!