Protein in urine 3rd trimester

Doc seemed pretty concerned and ordered a bunch more tests and moved my appts up. I did not have high blood pressure. My next test isn't for 4 more days. I looked online and of course preeclampsia was mainly what showed up but I'm wondering if anyone else has dealt with protein in urine and it been no big deal? They cultured it so I know it's not an infection. I've read low levels are common in pregnancy but I've never had it before nor anyone I know. So I'm just looking for any other experiences or info