Here are a couple of previous posts that might be relevant:
Video encoding (what is done when you export) is inherently complex and slow. We may be able to make suggestions to help you speed it up. But we will need more information. A good start would be:
What is your project video mode?
What are the properties of your source clips?
How many tracks are you using?
What filters are you using?
What are your export settings?
A few quick screenshots could give us a log of information and we could make some suggestions.