Your sevis needs to be updated every semester which your DSO does after you enroll for full time studies at school. This makes sure you are still at school and then only your I-20 and f-1 status are valid. By the time you will come back to school, your I-20 becomes invalid.
Since you have a visa, get an updated I-20 endorsed by your DSO, and return to the US. Not sure 100% though.