Hi I Am 19 Years Old And Have Been Taking

Hi I am 19 years old and have been taking LARGE hits of tobacco (75% tobacco/25% weed) out of a glass bong for about 3 years now. I just recently quit tobacco a week ago, but not marijuana. I am worried about my health after quitting, especially concerning risks of developing cancer. Whenever I would take these big hits out of the bong, I would sometimes SWALLOW a large amount of tobacco smoke and BURP it up minutes/hours later. I have been experiencing heart burn and gas problems for about 6 months now. Also, even if I take a deep breathe of fresh oxygen, I end up swallowing the air near the end of my inhale (burping it out later). Have I caused permanent damage to my health? (lung function, cardiovascular system, digestive system, etc.?)

I am very worried that even after quitting, I am still at risk for cancer (not just in the lungs) and other possible permanent, irreversible damage I have created.