Am i over reacting? Advice needed

I went to my boyfriends house yesterday and we got in an argument. I ask him what was it about and he didn't tell me for the longest time. Sometimes i feel lile he doesn't love me or pay enough attention to me so i brought it up... He tells me that its not true and im overreacting. He barely text me and he doesn't call me unless i call him but most of the time he doesn't answer. Proceeded to ask him questions like, is he happy with me? Does he want to be with me? Is he miserable being with me? And so on. He procrastinates to answer and about an hour goes by he finally answer that yes he is miserable. Why i ask him why he take a long time to answer again. When he finally answers my question he says " promise no to get mad" so i promise then he tells me. He has feelings for his ex. After that i cried off and on. I continued to cry today. Should i be worried anout anything? We were together for 18 months then broke up for 6 months and We been back together for 4 months