I hate it when I take time off, and the time I take off is lost because of the workload I face when returning.

If you are really under that type of pressure, they don't have enough people working for them, or your manager hasn't planned projects with leave time in mind.

I have been lucky to work for some great people that when I had to go that extra mile, there was extra rest to compensate.

Good luck on your project, and hope you get the well deserved rest you have earned when it's completed.