Back pain while pregnant

I'm 13 weeks and 4 days and my back is killing me! My husband insists on me calling my doctor but I don't feel like it's that serious. I'm trying to sleep so that I can work tonight and I'm not able to sleep because I can't get comfortable because of my back.. I don't know if the back pain is just due to the fact that I'm used to sleeping on my back and now I'm trying not to because apparently you're not supposed to but I don't know. Do you think I should call the doctor or just take a Tylenol. I'm a FTM so I'm really trying not to be that girl that calls her doctor about every little hiccup but my husband is insisting. Ahh. What do I do?