I need help saying no to a friend. help?

I have this friend that i've really only known for a year and (we're both in middle school 8th grade) he's a guy im a girl. Im afraid he has a HUGE crush on me(im not trying to sound conceited) cause he keeps asking if he, i, and my other friends that we sit with ata lunch can go to the movies and he ALWAYS flirts with me. I don't want to sound rude, but he's a HUGE nerd which isn't bad but he also guilts me a lot and i feel sorry for him, but i just don't like him more than anything but a friend. He guilts me by saying things like "i never go to the movies with my friends... we should go sometime. when could you pick me up?" and just last weekend was a parade and i asked my friend sitting at the table with me and this guy (i'll call him BOB so as to keep his identity safe) with me and BOB and i asked her to go to the parade with me. Then he said oh i wanna go too. I've never one out with any of my friends. So i said i would pick him up but never did because i was afraid to say no. See, (okay sorry but I have to explain the whole story before getting to the part about saying no) we had a project to do in one of my language teacher's classes where we had groups and did a presentation over WWII. We had a contest where one person from each group would go up and spell a word and the first people to misspell a word would go first to present their group project the next week. BOB misspelled the first word and started crying because he didn't want to go first. Not because he's a brat but because he just so soft. So i felt bad and i was scared because i didn't want him to keep guiling me into doing things and have me say no and have him start crying or get really upset. So, now, he keeps following me. Not stalking me, but in the halls if he sees me he walks right up to me and starts talking to me. After lunch when we go outside for a few minutes he follows me around and doesn't let me spend time with any of my friends except for the friends we sit with at lunch because every time(i mean EVERY time) i walk away from the two girls i sit with at lunch he follows ME and asks "where's M and L(first letters of friend's names)? Why aren't we with M and L? let's go find them." or if i spend time with other friend A, any she's REALLY weird he asks"why are you doing that? Let's go find L and M." It drives me up the wall because i want ot spend some time with my other friends and im really starting to not want to be his friend anymore because i want to just talk to my other friends without his standing behind me and saying things like "you shouldn't talk about people like that. ; why are you whispering? can i hear?" yes, i know that gossiping and talking about people behind their backs is wrong. Please don't yell at me for that. i'm just trying to make a point that he won't let me spend time with my friends and im too afraid to tell him to buzz off! i know i also sound really rude, but you have to try and sympathize. lie on 8th grade day where all the eighth graders get out of class all day and play on these giant inflatables HE WOULDN"T LEAVE ME ALONE. he kept following me and making me feel bad if i didn't go on an inflatable with him. I tried going with my friends and he would just stand there the whole time and watch and when i'd get off he'd make me feel bad! i TRIED SO HARD to spend time with my other friends than with L, because M is in 7ht grade, but any time i would go on something with my friend BOB would say" oh there's L, let's go say hi to her and see if she'll goon anything with us." Do you understand why im so upset? What makes me MORe upset is tomorrow is NJ HS day, say as 8th grade day but only for NJHS student (don't ask, something to do with grades) and i DON'T WANT HIM AROUND ME. I have a feeling that the reason he walks with me so much is beacaues we're basically his only friends. I'm not saying that to be mean to hi im just saying, that i honestly think we're his only friends. I just want to know a way to tell him nicely to please not folow me around at NJHS day because i want it to be fun and not..... i don't even know what to say.. just not im wiht me the whole time. please help and im sorry if im sounding hurtful. Im just SO FRUSTRATED.