At the end of the day if you are uncomfortable with the road users around you for whatever reason, get out of their way, you may not be doing anything wrong, they might be, but if it upsets you remove yourself from the position you are in.
I have to say reading your post makes me think the style of your driving may be the reason this happens and you might want to reevaluate the way you use the road when sharing it with other road users.
I can honestly say in the 30 years I have been driving I have never ever had a truck tailgate me on an open road where I couldn’t do something to get away from the potential danger and if you couldn’t see a way to remove yourself form the percieved danger you should look to get some more training.
As a driver you should have been able to get out of this situation quite easily, but it appears you chose to carry on as if there was no problem hoping something would change without any action on your part!
Even If you can’t drive progressively you still have to drive defensively, you appear not to do either or at least that is the impression your OP leads me to believe