what do you think??

glow says my period is due 26th of this month yet around the Internet I have been looking and they are saying that my period is due earlier than this.. according to glow my cycles are 33/34 days at the time but last month my cycle was 30 days and this changes all the time. I want to do a hpt ASAP but don't want to be upset if Its negative or if I do it way too early. what do you think?