Q: battery drain and overheating with 10.3.3

Apps can affect Mac performance, battery runtime, temperature, and fan activity - Apple Support

Yes, I have a late 2013 Macbook Retina. I've noticed a huge decrease. I've went from getting roughly 9 hours on a full charge to about 2 hours. It's absolutely terrible, and I'm not sure how it's even possible. I'm very frustrated with it right now!