HELP!!! BOY PROBLEMS!!!!!!!!!!?

this boy on my bus ive known for a few years. . . one day i gave him my number and we txted then we didn't txt for a long time. but we ALWAYS talked on the bus. then one day he txted me and we started talking again and then one day out of the blue he asked for a naked pic. and i told him no. then he wouldn't txt me anymore. but when i got on the bus yesterday i was in a bad mood and he was whispering my name and when i looked over at him he smiled. :) but things just dont seem the same. any ideas of how i can fix this? please! i do like him but i think were better as friends. i dn't want to ruin what we have. so Pretty please help. lol. thanks a bunch i really appriciate it.