Family won’t stop worrying and bugging me

I am 19 years old studying abroad, and my mom and grandma won’t stop bugging me. I have to call my grandma at least three times a day, text her whenever I’m going out, text her again at least 3 times when I’m out and so on. If I don’t do something from the above she starts feeling sick and hints that it’s because of me. When I don’t answer her call once she keeps spamming me with messages telling me to call her. It’s lighter with my mom, but she is panicky as well..once I forgot to turn the volume of my phone on and didn’t get her calls, when I picked up she was hysterically crying because she thought something bad happened.
I feel pressured to even go outside, because I have to keep texting and calling them. I can’t go to any events with other students because they’re after 7pm and apparently that’s too late, so I don’t have any friends at uni, and it also makes me overwhelmed.
When I try to talk to them about this they say that they’re just worried and they’ll call less, but they never do, it just continues on and on. The past few days I can’t focus on anything because of how overwhelmed this is making me. How should I talk to them so they finally understand that i’m not 10, that I live in a safe city and if I don’t pick up twice it doesn’t mean I’m in trouble?