You will not lose access to Pro immediately after pausing. Your account will pause itself at the end of your billing cycle, up until which point you will still have access to Pro. During the pause, all progress will be saved so you may pick up right where you left off when the pause is over.
You can see the date of your billing cycle listed on your Manage Payments page.
For more information on dates your account will pause, please see our help center article.