What Causes Recurring Pale Yellow Vomit On Brushing

For the last six months I ve been unable to brush my teeth due to every time I attempt to do so, I strongly gag, or vomit, and if I vomit it s mostly just stomach acids and it hurts my stomach. I don t know what to do, it started when I was smoking marijuana from a pipe, I later found out that I was using a crack pipe, instead of one designed for the substance I was using, and it s essentially harsher on my system. I figured at the time if I stopped smoking, it d go away, but it didn t. In the last three months I ve smoked about four times, haven t done so in the last six weeks. The problem isn t as severe now, but how long am I to do without brushing my teeth? The doctor has been totally useless about it, and I can t find any relevant information on the internet about it.