Should I add a 5th AP class to my junior year or is the workload too much?

I am a junior and I am not able to take Spanish 3 this year because it would conflict with my other classes, so I am currently a “student specialist” for prep chemistry, which is basically a TA except I also help by tutoring the kids in that class. I’ve been told that this will look good on my applications, but I’m not sure. One of my options is to replace this period with AP Environmental Science, but I don’t know if I’ll be able to handle the workload. These are my current classes:
TA Chemistry
AP Statistics
AP US History
AP Chemistry
AP English Language and Composition
Tennis
I also currently have two clubs to attend as well as a program called Bright Prospect (basically an extracurricular that helps you prepare for college) and am currently planning to add key club and national honors society. Other things to take into consideration are that I have the SAT/ACT this year and also tennis season starts during second semester so I will also be balancing a sport. I have all A’s and am currently rank 3 in my class but this is definitely a big step up from what i took last year. Would adding APES to my schedule be worth the workload?

I think that you would have the time. You only have 4 real classes, and 5, even all APs should not be too hard.
However, if you disagree about time, the TA will look better on an application than another AP, so don’t drop that.