36 weeks and peeing blood. Just stones??

So just over a week ago I went to L&D; after peeing a lot of blood. They sent my urine in to be tested and ruled out uti so we just guessed it was kidney stones. No other symptoms except days earlier I had back pain. The bleeding stopped for the week until this morning I woke up and I’m peeing a ton of blood again. No pain. I’m not familiar with stones. Is this really all it could be so I shouldn’t worry? Should I call my doctor to let her know or is it not a big deal?