what to do if the sex stops

my boyfriend and I have been together for a little over a year and at first we used to have sex on a daily basis. at least 5x a week. he was always asking me to send him pics when we weren't together and constantly saying he wants me. he's been a cop for a couple of years now and a few months ago I started a new job as an RN - both of us work the night shift. so because of our new schedule and routines we only get to see each other once or twice a week. usually when we do, we either eat or sleep together and that's it.
now we've gone from having sex 5-7 days a week to maybe once or twice. the other day he told me he was "too tired" and fell asleep when I tried to give him a bj. he stopped asking for pics. I send them once in awhile anyway and he still seems to enjoy them but it's just not as fun anymore. I'm trying to figure out of this is really because of our work schedules changing so drastically & him really being tired.. or if there's something more that I should be worried about 😒 please send me your advice ladies!! before my crazy ass blows up on him and ruins my relationship lol