I recently had an opportunity to serve as an altar server which was a huge honor as a new catholic. I received communion at the early service and wanted to know what is the protocol for receiving communion multiple times during the same day.
These links should explain the restrictions on how many times Communion may be received in one day. The first answers your question directly and the following four are clarifications for specific situations. If you have any further questions or concerns that are not answered by these links, please contact Catholic Answers directly.
Are Catholics only allowed one Mass per day?