Blindsided

I’m 29 and have been with my partner for over 4 years. We did long distance for 2 years, I followed him across the country, and 2 months ago we just moved back to our hometown and signed a 12 month lease. I was so excited and relieved to be back with him. Two nights ago, while we were going to bed, he said he loved me and we would end up together. Yesterday he took me on a date to the beach and we had a nice time. He told me he was happy and loved me. As soon as we got home, he broke up with me. No warning. No fights. Just says he has this feeling that it’s not right, and he doesn’t want to be with me anymore. He has worried about our compatibility before, but has reassured me since that he doesn’t feel that way anymore, and he would talk to me about it if he did. It is like a switch has flipped and there is nothing I can do. I have given him everything I have and I love him to his core. What do I do with myself?