The withdrawal agreement that has been negotiated between the EU and the United Kingdom provides for a transition period which is to last until 31 December 2020, and the regulations on the coordination of social security systems continue to apply during this period (e.g. to tourists, posted workers, pensioners and students). The law already in force will continue to apply. So there will be no changes for you for the time being.
We will inform about further developments in due time.