Long distance boyfriend broke up with me

My long distance boyfriend suddenly stopped talking to me last 6 months. For no reason. I initiated to communicate, but got no response. When I finally send him an email to get things straightened out, he responded and said “let’s call it quits. “. I am just heartbroken because I was ignored for about 6 months and he didn’t bother to let me know what was going on during that blank period of time.

I feel so nauseous from this news and don’t know what to do.... I guess it’s just takes time. I’ve known him for almost 4 years and he just suddenly changed his mind so quickly. I wished I was warned, but I guess he never cared and didn’t value or looked at me as a human being.

English is my second language so some sentences might be confusing. Sorry in advance and please no mean comments. Thank you.