scared that I'm losing interest in my boyfriend..

so my boyfriend and I have basically been together for almost 3 years long distance!! we're both 17 and I've really been in love with him for the entirety of these 3 years but recently something has just felt off. I obviously don't expect the whole puppy love phase to last forever so that's not it, but I've realized I'm never as excited to talk to him anymore because he normally lets me down by going to bed early anyway. we kinda show our love in different ways (especially over the phone) but it's really been bothering me recently because I just wish he'd send me little texts to let me know he's at least thinking about me but that happens once in a blue moon :(  we haven't really been as affectionate toward eachother recently. I really really don't want to end things and I could definitely just have unrealistic expectations but idk. I just really used to be head over heels but it's felt different lately. any advice?