I'm going to slow down even more when someone follows too closely behind me
That seems dangerous. Why would you slow down more?
I'm driving a slow car and the driver behind me drives faster. I'm sure he drives faster to overtake.
I'm sorry that this person is doing that to you. You shouldn't slow down further while driving because it could cause accidents. You should let them pass you and still remain in the slower lane to avoid fast cars.
I'm going to put on earphones and music so I won't hear anyone.
I wouldn't recommend putting on earphones while driving as you may fail to hear what is going on around you and you may end up in an accident and would cost a lot of money to repair or car, or worse, cause you death. I do hope you reconsider and just drive on the road safely.