You poor thing. My exH has a job which involves a lot of heavy lifting and has had this 3 times (none of which appeared to be caused by a particularly heavy load but it must have weakened the discs. Once putting a sock on after a shower made it go). So I do have some indirect experience.
Obvs everyone is different, but these are the things he took away from the experts (he's fine now btw):
Can happen with a twist (esp twist and push/pull eg pushing a wheelbarrow around a corner/pulling a heavy cart across sand etc), not always heavy lifting, though that doesn't help.
Take anti inflammatories straight away and stay on them for as long as it takes. Ibuprofen etc or might be prescribed stronger ones.
When able to safely, do anything you can to stretch hamstrings out. Apparently a great deal of pressure is put on the lower back by tight hamstrings. He still stretches them out when he remembers and it always helps. Not many ppl seem to be told this but it's a great tip.
It will gradually ease off, all his took probably 3 months ish and one was so severe he was literally dragging himself to the bathroom on his elbows, couldn't walk at all at one point.
When walking exacerbated it, he used to either suddenly drop down onto his haunches (knees wide but feet close together, straight back, bum near the floor) or put one foot up on the inside of the opposite knee while standing straight. He looked crazy doing it during daily life but it helped. All depends on which disc of course.
Physio/chiro/whatever you can get is really helpful and needs making a priority.
Once up to it, any and all core strengthening exercises will be good for preventing recurrence (giving the spine a strong framework around it basically). Altho very fit and strong he hadn't actually done a lot of core work, and since doing that his back is loads better.
NO heavy lifting or careless/twisting movements yet obvs, but any gentle movement you can do is beneficial. Esp the hamstring stretch - even tiny amounts.
Oh, and try incredibly hard with whatever drugs might be needed NOT to get consipated! His pain was always worse when he needed to go and codeine often meant severe constipation which made it worse. Diclofenac helped him a lot but he was off his face on painkillers (from the doctor) at the worst of it. If they drug you up significantly, be very careful about driving/making decisions. He was seriously spaced out a lot of the time.
Take care and hope it eases off soon. Xx