I really miss my mom and I'm scared that she'll...?

I'm eighteen and have just recently moved in with my older brother (just over a month ago) and my mom, who I am insanely close with) stayed in colorado while i stayed in my hometown in Louisiana. Literally, since birth, I've only ever spent at least three nights away from her, tops. At first, I was doing okay. Then it started dawning on me, cos my grandfather recently ped away while I was in colorado with my mom, that I might not be there with her...when she dies. It tore my heart apart to think that I might not be able to tell her goodbye. It scares me that I could not see her for years before she dies. As it is, I haven't talked to her in little under a month. I miss her and everytime I listen to My Baby by Blake Shelton I just want to pack up my things, drive all the way to Colorado just to hug her again. I can't bare the thought, but I know I need to let go and live my own live. What do I do? I've lost a lot of people in my life, and most of them I didn't say goodbye to...I can't let that happen to me and my mom...