Coffee and Caffeine FAQ

I've recently discovered the wonders of coffee (used to drink 4 cans of soda a day, got out of that, into about 2 cups of tea daily) but as far as research goes, I still have a few questions about effects that seem to take place during the caffeine-period a few hours later. After taking moderate doses of caffeine (eg. 2 cups of coffee or 1 can of Monster) I've experienced a few different changes, that after reading up on them, have proved to be symptoms, but I'm still not convinced. So here's a list, anyone want to fill me in on the actual known symptoms over things I might be exaggerating a bit?

*Personality Change- I've even noticed this as well as others...I seem to be more jumpy/happy when in a caffeine state..mostly all smiles..

*Hyperactive- After the caffeine kicks in, I'm jumpin' off walls..I'm 90% sure this is a symptom but running around and doing things I wouldn't normally do, like sing out loud? Could caffeine take you over that bad?

*Mood swings- Major mood swings half the time..one moment, I'll be happy, but if anything...ANYTHING...goes wrong, I'm pushin' tears...and even when I'm over it, I have trouble regaining happiness, and smiling is like a chore..whys that?..I know this was a symptom of energy drinks, was it the caffeine?

theres a couple other things that have been debated and I'm wondering about a solid answer for, or close to one..so opinions open :)

blood pressure, asthma (helps?), long-term effects (heart disease?) and any other useful effects, short term or long term

Regarding the first questions, I'm 15 years old, 16 in April. I weigh an average of 120 lbs and I drink caffeine regularly but I don't overdo it. I used to drink 4 cans of soda between 2-4 in the morning...which I guess is bad. I drank 1 energy drink every couple days for a week, then stopped. I drink tea every day (2 cups) and started with coffee (1-2 cups daily). So I'd take a swing and say my body should of worked up an O.K defense against something like caffeine, or am I wrong there too?

So, any tips?