constant AAE Error -6101 in Pro Tools 11.3.1 on OS X Yosemite 10.10.3, 003R interface

I have been struggling with trying to get back to a stable version of Pro Tools ever since having to upgrade Mac OS X from Mountain Lion to Mavericks/Yosemite. I was running Pro Tools 10 for the longest time on Mountain lion with a perfectly stable Pro Tools system with a Digidesign 003R interface.... could run tracking sessions at H/W buffer sample rate of 64 samples, with tons of plugins running and not run into any issues during recording and especially not on playback for mixing. Then with Pro Tools 10 on Yosemite, the playback buffer error messages started to come.... Increase buffer size or remove some plugins error 6101..... EVERY 20 minutes or so. I thought this may just be due to running Pro Tools 10 on Yosemite which is not supported so I did the responsible thing and upgraded to Pro Tools 11.3.1 (the newest version at the time), purchased all my AAX plugins I needed to purchase to continue mix sessions, and went through the optimization procedures for Yosemite. Now the playback buffer error messages are even more frequent, keeping me from getting any work done at all. Is this an issue with the new OS X Yosemite 10.10.3? Is this just Pro Tools 11.3.1 not working well with my 003R and the Avid 002/003 family drivers? Do I need to go back to an earlier version of Pro Tools 11 like 11.1.3? Is anyone else having these issues with Pro Tools 11 and running a 003R? Or if you are running a 003 family device and Pro Tools 11, which version are you on? or how did you fix these errors? PLEASE HELP!