Help i need love advice!

So i have been with my boyfriend for about 5 moths and i love him to death, he is honestly the best person in my life and the best thing that has happened to me. He treats me amazingly and i know he would never do any thing to hurt me. I could honestly see myself with him for the rest of my life. I don’t know what i would do without him. But here is my issue, i used to be the person who didn’t believe that high school relationships would last (we are juniors). So now i sometimes just start to think this will end someday because very little relationships last through colleges (if we chose to go to different ones) and stuff like that. And then i have had panic attacks about us possibly breaking up one day because i do love him so much. He has witnessed one of them and he always assures me that he is not going anywhere and that he loves me so much. But i still have trouble because i constantly worry about the future. Is there any way to stop me from worrying like that? Has anyone stayed with their S/O from high school through college and are still together? Please help