Medicine safe for baby?


So I have been having really bad lower back pain, starting last night, but I also found out I was pregnant yesterday. It’s getting better, but I was wondering, if it gets worse again, what over the counter medications are safe to take, and if this is normal? I’m also up to natural remedies, but I can’t take a bath at my house, the only tub is it roommates bathroom and has a drainage problem, so it’s gross, and I don’t want to scrub the tub and make my lower back hurt like that again (partner is out of town until late tonight for work, so he can’t help me). Any suggestions?