I Have A Foul Taste In My Mouth At All

I have a foul taste in my mouth at all times. I've been to the dentist and had a few cavities filled but the taste is constant and I think it's blood cause it taste like raw metal which is probably iron. I haven't been sick or had any surgeries or tumors I know of. I do smoke medical Marijuana daily for insomnia but only once a day maybe 4-6 hits. I think it's coming from my nose but I do not get nose bleeds or see any coloration when I spit Please advise .. home remedies would be appreciated.