I've had similar experiences recently, and I second the Metamucil suggestion! When I have a day or night that I feel like I have to go but don't pass very much, I take plain psyllium husk. That's all Metamucil is but with added ingredients to improve the look/flavor. I mix it in a glass that is mostly juice and a little water. It takes a few hours to work, but it works very well for me. The closest to a normal BM I've had in ages. I take it every day now, actually. It's good to drink some extra water after because, as I understand it, it absorbs water from the intestines. Also, I've read that it can interfere with supplement/medicine absorption so give yourself 1-2 hours before/after to take other medicines or supplements.
I hope it works for you or that you find something that does! Feel free to message me if you have any questions about it!