Marijuana in pregnancy

I’m currently 8 weeks along I’ve been an avid weed smoke for the last year. Weed helps with my severe back pain. I was prescribed lyrica which I stopped as soon as I found out I was pregnant. But I’ve been trying to stop smoking as well but the pain I’m in when I dont is unbearable I’m constantly in the bath tub or laying on the heating pad. I have two other children. The only thing that curves the pain i feel is safer than lyrica is marijuana. I’m so torn idk what to do I want to stop completely I just don’t know if my body will cooperate 😩😩