Yeah, I reached that conclusion in Psychology class as well, that I can't make everyone everywhere happy. I just think it's wrong of me to steal happiness away from others in order to have it myself.
Thats why I called you a Saint, duh
You're always try to make everyone AND yourself happy. Moving on.
YEAH I KNOW! The whole "I love you" think bugged me the first time she said it to me, too. At first I didn't know how to answer, and she got offended that I didn't say it back.
Alright. Is there ANY chance that you can find out how does she mean it? You probably cant figure that out from chatting online, on MSN or whatever.
Maybe if she told you "I love you" in person? Or I dont know, some other way.
Anyway, find out how exactly does she mean the love thing. Other than that, nothing stops you from getting together with her, unless she doesnt want to be with you, which isnt the case.
Anyway, Mishayla is mine for the moment, and probably will be for a long while to come, given the circumstances. Even Liz, my ex, approves of us being together. In fact, we have a date in 11 hours. The BIGGEST issue I really have is how to throw off Hannah without completely leaving her alone, I mean yeah, I did kinda hate her as the one person who stood in my way, but I also respected her as a vital part of Mishayla's life.
Stop saying "she is mine", because if you get too cocky, that might screw things up.
Also, since I know the typical Xer07, I assume that you will date Mishayla for like 2-3 months before you actually make a move 
Seriously, dont wait until you get married to kiss her. No really, dont.
Dont rush things, and dont wait forever.
Forget about Hannah. Just be her friend, hang out with her, and if she starts a conversation about you and Mish, then tell her the truth, and apologize to her, but dont back off.
As far as I can tell, you are taxiing away from the airport, and you are getting ready for lift off. Stop asking permission from the tower. You dont need it. The runway is clear.
Just remember that you only have 1 shot, or the plane goes boom as it gets off the runway.
I hope I made myself clear with all the plane stuff 
Last piece of advice:
Stop asking for advice, and trust yourself and your feelings.
"Cute Pokemon always get Parahax!"