Lower back pain.

I've known for two weeks that I'm pregnant. Based on my last period, I'm about 6 weeks along, but I think it's more like 4 weeks. Last week, I suddenly started getting pelvic and lower back pain that radiates down both legs. The pain was barely bearable and I could barely walk. Sitting on the couch is a whole puzzle. But once I find one position, it eases up a tiny bit. Yesterday I worked and walked home from work. That night I managed to sleep for a couple of hours, then woke up with severe pain in both legs. I couldn't sleep. A few hours later, I ended up taking two paracetamol, which I really didn't want to do because I'm afraid it might increase the risk of miscarriage in the first few months. I called my GP today and I'm curious what they'll say.