Why does he text me a lot sometimes and not so much other times?

OK so me and this guy have been talking for about three to four weeks at first he would send me sweet texts all the time, now he barley text me he works six days a week and blames him not texting as much on that, he said he would text me a lot at first because he wasn't as busy, and they just so happened to get more busy, he told me not to worry that if he didn't wanna be with me anymore he would tell me. should I listen to what he says or go buy his texting?! it is driving me NUTS!