Glow changed my DPO?

Sabrina
I got my positive OPK 4/2/17, according to Glow yesterday I would be 8 DPO today, I went to look at my chart today and it has changed my fertile week to about a week later and now it's saying I'm only 6 DPO? I haven't entered any different info so I'm not sure why it changed. It's also pushed back my AF start date by two days??