I read you're a smoker and worried about it , your lungs clean themselves up after 10 years you'll be recovered ( never fully of course ) but cancer usually kills those who go back to smoking and already had cancer ( got my gramma that way ) so your doing good so far no joke
a good diet and exercise is no b/s and will really help you over come any bad decisions in your past usually any way also cleansers help as well as keeping track of your cholesterol , blood pressure ,ect. and regular physicals to keep you from worrying.
Sounds like you have anxiety , I mean threw your post I can tell you worry , I myself gave in to xanax I wouldn't suggest the pill route unless you need it and if you need it don't abuse it nothing good comes from it ever.
To handle it there are actual herbs like st.johns wart? something like that sorry I don't have the name , also a therapist not a psychologist , I mean some1 who sits and listens for an hour not your 5 min drug dealer with a degree lol , helps alot as you can vent and confide in some1 without trust issues involved as its by law you can trust them wich is always nice.
I think you could use that , vent , assistance on choices and getting threw things , thinking things over and also seeing about your panic attacks they help you keep track of them , teach you breathing methods .
Huge Hint that Truely works , anything that makes you speed up is bad including caffeine , adderall or any illegal substance , sugary foods like candy and even ice pops .
You also have to learn to calm down you seem to have panic disorder ( its anxiety with panic attacks ) just learn to calm down , turn off your anxiety , say everything will be ok or resolve your problems .
Stay far away from lithium unless it's that or an insane asylum , I've known a few ppl on them and 1 stabbed my uncle ( he's fine ) with a screwdriver when on it b/c she was a little mad , there's sooo many other pills for bi-polar disorder that work and you should be rediagnosed before you jump on that [email protected]
I hope I helped somewhat as I know I didn't answer everything but I am sincere in hoping you end up ok and that a therapist could do you good trust me on that .