How to manage my relationship

I have been dating my boyfriend for a year and half now, it started out as a long distance relationship, truly it was okay in the beginning things were moving smoothly we talked on a daily basis and chatted frequently. Even when I did come back things were still good our relationship was moving smoothly, it felt like I didn’t miss him much because of the constant communication we always had. Recently like a month ago, I sensed a change in energy, he barely called me, I always texted first, he didn’t check on me. When I finally got to talk to him, he said he was going through something which he will tell me about in person. But when I suggested to meet him in person, he ignored my message. He’s still ignoring my calls and delays to reply my messages. I love him so much I don’t want to give up on him but I seriously don’t know what to do at this point. Was he not serious from the start why is he pushing me away. I am depressed and emotionally exhausted by his actions. What should I do