my heart is acting weird?

[anthony]

i am a 16 year old male 149lbs. i smoke, drink, take adderall, drink coffee, smoke marijuana, eat a lot of fast food,and skateboard lol. They arent the best for my heart which is why i quit them all last week besides skateboarding. my heart will sometimes randomly beat funny. its the same feeling as when you are told terrible news or are in huge trouble. that weird feeling of your heart just dropping if you know what im talking about. i dont think its anything too serious. i just wanted to know if I would be okay if I quit smoking and coffee etc, and start eating healthier.