Deadlines get us mobilized.
Generally it’s good to have a target to work towards. It makes the goal into something tangible and infuses motivation into the work.
The one problem that can come up is when, instead of the end-time focusing you, it pressures you. Instead of stimulating creativity it compresses you into restricted consciousness.
Your mind is a blank. The best thing to do then is to breathe, decide that it’s not the end of the world if you miss your deadline, and make a new deadline.
Do something fun, get away from your computer and come back fresh.