NEED ADVICE

I’ve been “seeing/talking” to this guy for about 2 months now and in the beginning he was sweet, replied back fast, would give me compliments, always tried to see me, etc. let’s just say he was really romantic in the beginning and showed interest in me but now I feel like he doesn’t show as much interest in me anymore now that he has my attention. He takes forever to reply back, he doesn’t give me compliments (I don’t need him to do this to make me feel wanted but it feels good to get compliments) or let’s me know that he’s thinking about me, & our conversations are sort of dry now. We haven’t seen each other in about 3 weeks and he hasn’t even said he missed me or try to make plans to come see me. He recently just went back to college last week. Before he went back to school, we used to see each other about 2-3 times a week and now we don’t see each other. It just seems like he isn’t showing as much effort anymore and it’s driving me crazy. I tried talking to him about it and he always makes up excuses to justify his actions. I keep telling him that if he’s not interested in me anymore to please let me know but he keeps saying that he still wants to keep seeing me and that there is no other girl but I’m just confused as to why he is acting like this now. When we see each other in person he is the COMPLETE OPPOSITE. He’s very sweet and caring to me in person but once we are not in each other’s presence, he acts different. I’m starting to feel some type of way, I miss how he treated me in the beginning. I really like him and I want to see how this goes but I don’t know what to do. Should I end it or try to talk to him about it again? Please no rude comments.