I worked for one place , not truck driving , , I was a property manager , supervising a staff of five and responsible for a budget of right at a million dollars every year , and got called into the office on a Tuesday after working there NINE years and got handed a severance check and told not to come back tomorrow .
OP...whatever you decide to do just remember that a day after you're gone they won't even remember what you look like. A week after you're gone they won't even remember your name. Companies like that go through a lot of drivers. You're just the most recent one.
Then don't worry about it. If you were honest, and your side of the street is clean, and your motives were sincere, then just move on and don't worry about it. That's all you can do, and that's what you would want from someone else if the roles were reversed.