You can find more videos online such as iTuneU or the course http://www.thegreatcourses.com/courses/understanding-calculus-problems-solutions-and-tips.html (the latter a bit expensive). However if you think you are understanding the material then a tutor or watching more videos is unlikely to help much. What I suggest is practice, practice, practice! Get the book “Calculus Problem Solver” and turn to a chapter covering what you are currently studying. Start working problems with the answers covered up. If you are getting these right you should get them right on the test, but my guess is this will be both diagnostic and educational. Diagnostic in that I expect you will have difficulty solving these problems without referring to your text or (for the ones you can solve) doing so at a decent pace, and educational in that if you keep working problems until you do get them right you will be learning the material and be able to solve them at the speed you need to finish the test in class.
If your only option is Stats next year (which is a big step down from BC), check whether you’d be allowed to do AB this year, BC next year. Some schools have that progression and it makes a lot more sense. Or is there a community college nearby where you could take the next level after BC?
But really stressing out for BC as a junior, only to take stats as a senior, if you could take AB-BC, would not make a lot of sense.