Advice ? Thoughts?

Hi! Interested in opinions/I need advice/ I need support…Gonna keep it as short and sweet as I can.

My boyfriend is on active duty he’s a marine, we haven’t seen one another since February 26, we text every day but in total we have FaceTimed like maybe 4-5 times since he’s been gone. We never talk on the phone. He seems distant the last couple of days, and a little short. Hes a great guy, and not somome who I’m even remotely concerned about cheating… but is the shortness a normal thing and the lack of communication? It’s the same thing every day, “how’s your day sugar” “how’s work”. Basic texting convo that doesn’t have much depth to it… I’m new to this lifestyle and he’s the first guy I’ve dated in the military.. I’m being patient and haven’t brought it up because I feel he has enough on his plate, but I also feel a little frustrated the last few days. Side note: I’m about to start my cycle so I don’t wanna be overly sensitive. Is this the norm? Do they stay so busy that he can’t put in a little more time to talking to his girlfriend who’s 21 ish hours away ?? He says he misses me and daubs things like “I can’t wait to have you back in my arms”but I feel like he has kind of put me on the back burner. 😢

just need some help and reassurance…