Automatic Transmission Shifts Hard

I have a 99' Civic Ex with an Automatic Transmission and have been having some problems since I got it. When I slow down and make a turn onto even a slight hill, the transmission kicks in really hard to I'm guessing either 1st or 2nd gear, but it kicks in really hard like I feel as though my tranmission is about to fall out. It also sometimes doesn't shift right when i'm driving at high speeds like I feel as tho it should shift from 3rd to 4th gear but it won't and my RPM will be really high so pretty much what I have to do is take my foot off the gas a little bit to allow the car to shift gears. Also my car lags a lot and is sometimes really really slow.....could my transmission be causing all of these problems and if so do you guys have any suggestions besides getting a new tranny?

I came across this Honda technical bulletin that describes what you’re talking about. I wouldn’t consider it a recall but it may apply to you:

http://autorepair.about.com/cs/faqs/l/bl127e.htm

When was the last time you did a tranny flush?

I haven't done that yet but I'm pretty sure I am going to now. I think maybe it will help it out if I flush the tranny.