Open Question: Why do I keep switching addictions?

Got drunk for the first time when I was 12. Drank more or less 5 times from then till I was 14.
When I was 14 I started experimenting with drugs (Cocaine and Weed), and started drinking heavily twice a weekend
Then when I turned 15 I started REALLY experimenting, smoked weed every day, and ended up addicted to heroin till I was 17.
Went to rehab, got off the heroin, and started smoking weed a lot again.
I am almost 19 now and I just recently quit smoking weed and cigarettes, by choice. (I do not do any other drugs)
However, I am now an alcoholic. No doubt in my mind.. I recently went through something very traumatic and I belive that this is what caused the switch. I dont want to stop drinking though. I just want to know why the hell I do this to myself?
Will I ever not be addicted to something again? Will I become addicted to food, sex, relationships ect? Is there really such thing as an addictive personality? I am not one that deals with change well. I Don’t even know what’s up