Intense lower right back pain

I noticed intense back pain on my right side at 4 weeks, I've been thinking it's just a pinched nerve. I'm 12&3 now, and when I do anything physical, even just being on my feet for too long, it gets really bad. The only position I'm comfortable in is criss-crossing my legs sitting up. Trying to lay down will bring me to tears at times, there is no comfortable position, it hurts so bad. I don't think my husband believes me when I express how sore it is, he probably just thinks I'm being a baby about it. I'm not even showing yet so I doubt it's caused by pregnancy.
I have a doctors appointment tomorrow, but does anyone know what it could possibly be? I'm in so much pain 😭