My cycling averages have slowed way down over the last 2-3 weeks. I went from averaging 18.5 to about 15.5 or 16 mph. My top speed used to be 23 and now its 18. I don't know what my problem is. I did take a weeks vacation between all this, but I managed to run at least 4-5 miles every day and did tons of walking. Any suggestions on how to get my pace back up or what the problem could be? I'm getting nervous, I have my first triathlon in less than two weeks.

Thanks!