yeah, it definitely seems to be connected, also for me it got a lot worse, i always had it a bit but yeah two years ago, about the same time as i started using the sugar free versions.
i've basically kicked out caffeine altogether, except the tiny amounts in the cacao, which probably amount to about half a cup of coffee that gets spread out over about 5 hours when i have my morning breakfast cacao/salt/milk.
i hope you can solve this issue also. it's really messed up because as i discovered it advances into double vision and that has been a real kick in the nuts for me as a programmer.