Usually, a slow upload is due to a large order or slower internet speeds in your area. You might need to contact your internet service provider about upload speeds. You can check your internet speeds with this website.
If you are uploading a lot of images and your file sizes are very large it may take longer. When uploading large orders through hhschools or hhsports, you may want to reduce your image size to no larger than 11x17 at 300ppi.