I honestly don't know what to do

Please be nice! I'm in a long distance relationship (dated a year before) and its hard but i love my bf so much. Its just i don't know what to do. I saw him this weekend and when i'm with him i am the happiest girl in the world. But now that we are apart i can just cry myself to sleep because i'm upset. I don't know if its just my hornones or what but this makes me soo upset. I just don't know what to do and get mad at him but its not his fault and i am just so confused. I know i love him  and i trust him its just idk why i get so upset like this. Please give me advice