1. ever heard of a condom, jackass?
2. I wouldn't go out with someone against abortion.
3. If you have repeated short term pleasure, you'll be happier in the long run.
4. There are a lot of mental benefits of having a boyfriend or girlfriend.
5. I'm not gonna be abstinent!
Condoms aren't 100% effective. And they definitely don't protect you against STDs. Go ahead and do what you want, I can't stop you. But keep in mind, it's people like you who spread STDs.
But at least keep this in mind, and try to limit yourself. I have great self-esteem, and have stayed abstinent through high school. The good relationships in high school are the ones with people who actually encourage you to be a better person, not with some skank who sleeps around with everyone and gets STDs. I'm not telling you to not have a girlfriend, I'm just telling you to think before you become consistently sexually active.
And where do you get your "less depressed" information? It sounds to me like you pulled it out of your ass.