It was the same for me when I would go home for break! Mom would be in my room at 8 am asking me when I was going to get up and start my day, did I always sleep in this late when I was away at school, etc. It drove me nuts!
Just wait 'til you graduate and get married...then it's when are you coming home, we haven't seen you in so long (even though they don't come visit you), can't you take time off work to come see us, etc., and it's a guilt trip of a completely different sort!