Severe back pain..help

Amy

34+3, he’s super low and is quite a big baby (95th percentile). The past 2 days have been really hard with painful back ache. I can’t lift my legs..I can’t walk for more than 10 mins and I’m walking like a 90 yr old woman. I’ve tried hot water bottles on my back to help..anyone got any good suggestions that may help?

Thank you