Partner overseas, uncontrollably sad

Aimee • 18, with the love of my life💍 and I'm a musician 🎶💞
My partner had to go back to his home country early this morning for his great-grandmothers funeral. I couldn't go with him because I couldn't afford it. He's only gone for a week but we haven't spent more than a few hours apart for almost a year and I'm already so uncontrollably sad that I can't focus at work and my anxiety is getting really bad. I can't talk to him often because the place he's in is really rural and there's no service or wifi.
Does anyone know what I can do to not be so upset?