Spitting Up Blood With Cough, Lightheadedness, Sharp Pain In Chest, Neck And Shoulders. Addicted To Smoking Cannabis. Is This Serious?

Hi, i have a very serious questions. I have been smoking cannabis for about 5-6 months now, aft first very light, but nearing the last few months it was heavily. i would smoke 3-4 times a day, and at each session (my smoking time) i would smoke around 3-4 bowls (where you put the cannabis in the pipe or bong). over the last few months i also have been mixing my cannabis with tobacco. When i first started i was fine, i felt okay, but after a few weeks when i would smoke with the tobacco the taste would make me feel sick, but i still continued to smoke it. keep in mind that i do no smoke cigarettes, but i do add a little to my weed. one cigarette would last me a few days. Recently in the past 3 weeks i have discovered that i was spitting up a little blood when i would cough or spit out mucus. i would also feel sick after smoking at times, and light headed. just recently i have has sharp chest pains, shoulder, neck and side pains where my ribs are located but closer to my back on the right side. im very paranoid and i thinking the craziest things. Do you know what is wrong with me or what could be the problem? I went into a walk-in clinic this morning and they said nothing was wrong with my heart or lungs, but i get a sharp pain in my back and chest every time i try to take a deep breath and i find that it is very difficult to sleep on my back, chest or sides. Please help me! i seriously hope it is not Lung cancer or something as serious! Thank you