lower back-pelvis strain during paused squat

Hi,

Yesterday I hurt my lower back and pelvis quite badly during the paused squat. I still felt strong during my second-last rep but had to readjust my grip because the weight was slipping out of my hand.
During the last rep, when I picked up the weight it felt like my lower back muscles completely “gave in” and I had to let the weight drop back on the floor while my lower back was in a “wet noodle” state.
It took me some time to actually get up. I experience pain especially when sitting a while and standing back up. Yesterday evening it probably took me 5 min to get out of the sofa as it felt like my lower back couldn’t handle the pressure from standing up. I probably performed one too many sets and definitely have to order a belt, but do you guys have any advice on how to recover from this as quickly as possible?
Is this the kind of pain that could get better from doing some light exercises?

Thanks in advance,
Gregory