growing up and independence

I'm a 19 almost 20 year old who's going to school in another state than my family. I've grown up very close to my family however now I have a boyfriend ( of 3 yrs) and we're pretty serious. Now it's nearly thanksgiving break and my boyfriend has invited me spend thanksgiving with his family in another state than my family. Now my mother is outrageously upset about it and I don't know what to do. My boyfriend last year skipped a cruise with his family to spend thanksgiving with my family and see me when I came home. It's the first time I've ever missed any major holiday with my family. Is this a normal reaction or did I really mess up.