Anice it could be a combo of everything together at once causing your pain to climb. But, I would do what you said and play with the Tens Unit and find your right number. I truly do not understand what the peson told you about
cranking it up high, that really makes no sense. With mine yes, I was told when I turned it on every time to go a little higher then back it off some where it was more comfortable, but not like what you were told. I am afraid if cranking it up high is causing an increase in your pain, then the use of the Tens Unit is a wash. You have already had a good day using it as you were instructed in the very beginning. I think I would stick with that
plan of a lower setting and be more comfortable, inceasing the pain is not what a Tens is indicated for.
Yes, using your disability thru your job means if you return to work the benefits stop. Then if you were unable to do the work after returning, you would have to file a new claim all over again, You would not just get to resume benefits automaitically. So, its best to be physically fit and able to work when released.