I'm sorry you're having so many stomach issues.
I can understand you being concerned and scared about telling the gastro doc about your marijuana use, however, it's imperative that you do. Not only will it give him more information about what he might want/need to look for, but it will also allow him to prescribe a SAFE treatment/medication plan. Even though marijuana is "natural", it can still interact with medications, so it's very important that EVERY doctor you see knows about your smoking so they don't inadvertently prescribe you something that could cause serious interactions.
I would also strongly suggest that you NOT force yourself to vomit, even though you say it relieves your symptoms for a while. Vomiting itself can be very hard on the esophagus and digestive tract, and forcing yourself to vomit can make it even worse. It's very possible that although the vomiting seems to relieve your symptoms temporarily, it is actually doing more harm/damage.
You may also want to try raising the head of your bed to see if helps you sleep without getting that acid feeling creeping up. You can purchase bed risers at places like Walmart for just a few dollars. They come in a set of four, but you would only use two - at the head of your bed. This will put you in a better position for sleeping that will help the acid in your stomach from "sloshing" back into the esophagus. You could try propping yourself up in bed with several pillows also, but this is not the ideal thing - the pillows can move during the night, making them basically useless for the cause and also, sometimes if you're just propped up on pillows, you end up actually putting more pressure on the diaghram/upper stomach area, which again can cause more acid to slosh up.
Have you tried any of the over the counter PPI (proton pump inhibitor) drugs, such as Prevacid or Prilosec? You may want to give these a try while you're waiting for your gastro appointment.
As for the coffee - I know how difficult it can be to stop drinking - I, too, am a coffee drinker. The coffee itself can be rough on your stomach, but a lot of it is also related to the caffeine in the coffee. Maybe try decaf (or 1/2 decaf and 1/2 regular at least until you get used to not having the caffeine)- and see if it helps any.
One last thing - avoid eating for at least two hours before bedtime or even laying down. The fuller your stomach is when you lay down, the more likelihood there is that you'll have the reflux/heartburn symptoms.
I know you're worried, but you're definitley much better off being honest with your doctors.
Best of luck.
You might have celiac and you may need a gluten free diet; do some research on the internet. Acid reflux has alot to do with what we eat. I have recommended a nutritionist to others and it seems one would really be beneficial to you also. Look for one that will do a blood test to see your red and white blood cell counts; pay for the visit out of pocket. First consult will run about $200 and includes the blood test along with direction and guidance to a healthier you; it is worth it! For your sake, cut that one habit out, smoking of any kind isn't good for any of us. :-) I wish you the best in getting better!