How could this change sooo fast!? :(?

I have just finished my 6th grade year.. So that's middle school. and it was my first year. I met a boy named Sam, our lockers were next to eachother's and we sat next to each other in homeroom. He'd always flirt with me..He circled my birthday in his organizer. Sam and i liked each other at the same time, we just didnt know. After the first 3 months of school, everyone got their seats changed so we werent that close. So we were standing in the lunch line together and a girl named macy said to me(jess), "Jess, didnt you go out with sam?" and i was like "no..?" and then Sam was like, "No one likes Jessie". and i was really upset because i really liked him..i cried that day when i got home from school..