Katie,
I think the 1st question that was asked about being conditioned to iignore your alarm because you know you have set it before you actually have to wake up is probably the most obvious place to start. I would suggest you set your alarm for the actual time you need to get out of bed, and maybe your response to the alarm will become, well, alarming! If we know we can condition our minds to awake at a certain time without an alarm clock, its certainly possible we can condition ourselves to ignore an alarm clock!

Beyond that, I looked at your bio to see your approx age, to see if possibly you have obstructive sleep apnea, where you get so sleep deprived from constant awakenings to stage 1 to start breathing again, that you rarely get into Stage 3 or Dellta Sleep, which is where the real restoration happens.(Not in REM as I saw posted here somewhere) REM is critical to a healthy mind, but Stage 3-4 is where your mind gets restored and takes short term memory and makes it long tern memory, among other things. I know this because I have Severe OSA and even with CPAP therapy to keep me breathing, I rarely get into Delta, and it is extremely debilitating.

The fact that once you realize you need to be awake, you become alert enough to function tells me that there is nothing serious going on, yet anyway. After 7-8 hours of sleep, it take me anywhere from 30 - 120 minutes to be able function well enough to leave the house and be productive and lucid.

Last question I would have for now is, are you taking any meds before bed?

Good luck
AzManatheart