HD Sequence export freezing then increasing time

Hello,

I am trying to export a project that is due tomorrow and I'm experiencing some issue.

It is a 40 min sequence and the place where I am exporting it to has more than enough space for storage. I formatted it to H.264 and am using the preset HD 1080p 23.976 - no other functions adjusted.

When it begins to export, the clip starts at 1 hr, then increases to 5 hrs, then stays at 15% for about an hour. then, the time increases on intervals of 5 until the time remaining says 7 hrs.

I would very much like to go to sleep knowing that my video will export and be fine... is this normal?

-Aidan