This is quite common when players change club and get re-added to their local league system. As a result, their subsequent results are entered against their new ID causing SquashLevels to treat them as a different player.
You should find that the system spots your 'other' player and asks you to let us know if you really are the same person via a form at the top of the player detail page but, even if not, please let us know and we'll merge the two sets of results. It can all be sorted - we have the tools.