Is my reaction overprotective or normal?

I am male, 19, dating a female, 20. We have been together for about 3 months and have known each other for about 5. We both have a lot of trust and insecurity issues, and so we strive to make trust a key point in our relationship. It has been perfect so far.

Right now I am away at college so our visiting is very limited until we get a place together, which will hopefully happen by this coming summer if all goes well.

The issue at hand is over the best friend of my lover, a male. I have never met him, never seen him, never talked to him, and no nothing but what my girlfriend tells me from back home. He is apparently gay, and just a close friend. According to my girlfriend, they have never even hung out, and are only friends through the phone and internet because he doesn't have a car. I am ok with this of course, no problems here.

Recently, my girlfriend's sleep cycle has been really messed up, and she usually doesn't sleep at night. Instead as she tells me, her and this friend just talk on the phone or online through the night to keep each other company and entertain one another. Made me feel a little weird, but still no problem. Nothing I can't deal with.

Today, she was telling me about a funny conversation they had last night. It was then that I realized I was not friends with him on any social networks, and hell, didn't even know what he looked like.
So I told her I was gonna friend him. After all, she had friended all of my friends. In any case, she made him sound like a really fun guy to talk to.

So I go onto her myspace to find his profile... her friends were hidden so I had to ask her to fix it. Unfortunately, there wasn't much to see. His profile was just a blank page with a couple pictures on it. All the boxes had been removed.
I am decent with computers, so I decided to view the source code for his page to see what all was hiding on it. Also, remember that I am very paranoid and overprotective.

Well turns out my girlfriend is his number 1 on his myspace, and there were comments from some girl dating back only a month, saying how much she loved him, calling him baby, etc.
Obviously last month he wasn't gay.
So instead of telling her flat out, I decided to ask her about it first. I asked her if he was always gay, and said I have reason to believe otherwise. She then tells me he's been bi his whole life, and only 2-3 years ago he became gay. I know this is a lie.

So, I see 2 possible solutions. Either she is lying to me, or he is lying to her, with some alterior motives. Am I wrong?
Am I losing my mind, being extremely paranoid, or overprotective? Should I forget the whole thing? Is it normal that after I saw that page, I felt sick and terrible inside?