Pulled back

I was walking down the stairs holding my sons hand and all of a sudden my lower back just seized up and now it’s been two hours and I can still barely move it. Any one else have this happen? I know I should go to the hospital but we are in such a covid hot spot I’m really scared of getting sick, plus with the government shut down everyone has been outside in the snow so the er is full according to a friend who works there. I just don’t know what I can take to help it also in 25 weeks pregnant