From mainland China to Hong Kong, Hong Kong to the Philippines, back to Hong Kong and back to China!

Hey everyone,

I just bought tickets from Hong Kong to the Philippines for my winter vacation. I am a student in China (mainland) and I have a one entry (that I made once I entered China so I can actually go back home or leave China once). I wondered if entering Hong Kong (use half of my entry) then leaving for the Philippines and coming back to HK then to mainland China could cause a problem.. I am Canadian and I don't need a visa for HK but would entering HK again use up my Visa?
Thank's a lot !