Currently it’s the second week of April and my Seniorites is hitting the worst at the moment.
An advice for people who are trying to take a lot of AP classes your Senior year, DON’T.
There are a lot of stuff that needs to be done your Senior year, such as writing applications, filing for financial aid, shopping, extra-curricular, etc.
I would say unless you are used to the workload, take 3 APs max.  
Just take it easy, but not too easy, and try your best in 2nd semester to retain your grades (especially the classes you need for graduation).
Good luck to all other Seniors out there struggling with Seniorites.