Tapering is hard. Especially hard if you feel a bit behind in your training leading up to your “A-Race”. Trust the taper and don’t try to make up for missed time or think you can add more fitness before race day. While this article focuses on Ultra-Running, the principles are the same when applied to Triathlon.
Pre-Race Do's and Don'ts for Ultrarunners - Jason Koop (trainright.com)