i'm really upset at my best friend?

I had no idea what forum category this goes in, i hope this is the right one.

I do not know what to do. I am mad at my best friend. We decided to take the same class in college for Fall 2014 semester. I actually was sitting next to him in class but then my other friend asked me to sit next to her and the friend (who this post is about) told me its okay to move my seat. Well at night time, when i am at home, my friend called to talk. So we were talking and randomly my friend says he is in love. I'm thinking "what?" but i tell my friend sarcastically "congratulations". Anyways he said he was in love with my friend from our class. Now that is what got me mad because she has a boyfriend and is happy in her relationship. I told my friend he better not mention anything to her, because he doesn't really know her all that well. I think my friend was teasing me because he likes to tease me because after he kept going "are you jealous?" "your getting jealous are you?". We used to date but decided that we were better off as friends and somehow went from dating, to fighting about why we stopped dating, to apologizing, to being best friends which has been working out well no problems, and now we are talking the same class and doing this college thing together. I do admit, i still like my friend and everyone believes he likes me still but I am hopeful we can date again. I am going to be corny here but I feel like Steve Urkel waiting for Laura Winslow. Maybe i should say I am moving to Russia to get things working again :/

Now another thing got me upset. He told me the guy sitting next to him asked my friend why i was staring at him. I wasn't staring at my friend, I'm sure everyone looks around the classroom. I also do not believe that is true because i never saw this guy ask my friend anything and i was sitting pretty close to them but not at the same table. At one point my friend was making funny faces at me so I made some back ( class was getting too boring professor kept trying to fix something not working on the computer), so maybe that's why this guy thought i was staring at him but I really wasn't. But i'm not letting what a guy who i never met in my life before get me upset, i do not know why my friend had to tell me that because it kind of bothered me. I wish my friend did not mention that part but i don't believe that actually happened as like I said, i didn't see the guy lean over and ask my friend anything except passing out handouts. Do i have the right to be upset over this? He said he is in love with my friend, but i don't believe him since he likes to tease me alot and for a half hour kept asking if i was jealous, and then told me what this guy supposedly said about me :/