Making her a coffee sounds like a nice idea, maybe you would be able to have a chat while she drinks it. You could be honest about how much you care for her and let her know that you're not trying to guilt trip her. Maybe she wouldn't believe that but I think your honesty is important and people need to hear how much they are loved.
It's very hard not to worry about people you love. Do you have ways to look after yourself and try and get some time to relax? Keep posting here if it helps to talk through things.