Time after time7dpo. The first seeds of doubt have been sown; watch them sprout over the next 24 hours.
I think I have seen the end of the trigger (HCG shot), have had a series of "is it, isn't it?" lines on HPTs over the last couple of days with this morning's being more likely imaginary than not. My temps are high, very high for me in fact. If I was taking my chart as sole evidence, I would be celebrating already. However, my twice a day progesterone pessaries are as likely culprits for this as a developing embryo.
The reason for my sudden lack of certainty that I have two beautiful babies growing inside me (ok, one, the second one is a bit of creative accounting on my part), is that I noticed my first symptoms as 6dpo on my last pregnancy. Now I know every pregnancy is different, and that 7dpo is early (but please don't tell me you didn't test positive until 15dpo - you just weren't trying hard enough), but the testing phase has begun, and it's impossible to ignore any signs that aren't 100% positive. Only time will tell, most likely the next 72 hours of it.