Oh and I never had a chart go triaphasic, but it can be a good sign. There have been ladies though that had triaphasic charts, but weren't pregnant...so, I guess it doesn't tell you anything for sure.
Sorry to be so nosey, but what is your cm like? I noticed about 10-11dpo, mine changed from creamy to almost watery with bits of creamy in it. I never had anything like it before, but I'm sure everyone is different that way too!