Over Sleeping. Is highly appreaciated?

I have a strange over sleeping problem developed over past a year. Everything was normal before that. I do not have day time sleepiness problem. Only problem is in waking up. May be in the mng or after noon nap. If I do not sleep, i do not have any problem. The problems is as follow: I set my alarm, say 6:00 in the mng. Most of the times I hear them at 8:30!! It ll be continuosly ringing without disturbing my sleep. Sometimes the alarm bell syncs with my dream (difficult to explain) and as a part of the dream (say a phone call ring in my dream that I reject) i turn it off. Sometimes I wake up but I wont be able to open my eyes, the sleep is so intense. This problem is everyday. Doesnt matter how important an appointment of that day is or an exam! However, from past a month this problem is slowering down. It happens oly a few times now. Your help is highly appreaciated