Congratulations on your engagement!
While I have never felt like I loved someone too much, I have lived with the feeling that something awful would happen to my loved ones. I had a hard time a few years ago worrying about my parents dying suddenly, like in a car accident. I have also worried a lot about my Mom. I still have these worries though not as bad.
My conditions tend to come and go (though they dont go away completely) so that could be how I overcame it, meaning that my anxiety subsided for a while. But I did have some insight into my worrying about loved ones 2 years ago. A lot of it came down to low self esteem, I thought that all the people I loved and anything that brought me happiness would be taken away from me because I felt like I did not deserve them. I am not saying that is you have low self esteem, just that is what I found for myself.
Worrying about things beyond your control I think is pretty typical to GAD. Natural disasters, your health, world/political events, your loved ones... All stuff you dont have much control over. All I can say is to just do your best in taking care of your health and encouraging your loved ones to do so as well. I would add that if you are in a more calm state of mind and something does happen, like an earthquake, you will respond much better than if you are panicked to begin with. I know thats easier said than done. I do try to practice deep breathing to stay calm, but mostly I just try and do things to keep my mind busy so I don't think about things. That is not necessarily healthy so I would suggest just trying things that are supposed to be calming, like meditation, yoga, deep breathing etc.
Finally I do think it is a good idea to not research things. I know that can be very helpful to people suffering from GAD. If you can take a break from your computer for 1 day or just from researching and fill in that time with something you like to do or something to reduce stress you may find it helps.
I really hope you can get some relief from this, I wish you all the best!