What Causes Shortness Of Breath And Sudden Dizziness?

. Almost passed out while walking the other day I felt really dizzy and saw Stars. I almost buckled to the ground and I was helped too buy a couple before collapsing felt extremely dehydrated prior to and was given a some kind of ventilator saying when at the hospital which I think was a steroid of some kind. They said ,I think if I remember correctly, it could have been be possibly a pulmonary and even cardiovascular issues that I shouldo see my family physician along with a specialist. I i will do this but I might not be able to get to it for a little bit. until my insurance is reactivated. what do you think this possibly could have been? I also had shortness of breath .I haven't been taking that great care of my body in the preceding month as well and smoke cigars 1-3 times a day. lately I feel like ive been really exuasted at times only on occasion & dont sllep for many hours at a time on any regular basis.I realize that this is all speculation but that's what I'm looking for from you if possible and I won't hold you to the answer,as obviously as I know ,official tests and stuff has to be done in proper format ,but i just wanted your opinion as I wanted to see what ,amongst many possibilities,what are the more likely scenarios.are many possibilities you could be thanks again.Thanks