I was suppose to get my period on the 27th of September, per <a href="https://play.google.com/store/apps/details?id=com.glow.android">Glow app</a>. Still nothing. We have been TTC the past 3-4 months and now I am finally late. When I tested 2 days after what I thought was my missed period, it came back negative. so I tested this morning when I woke up and it was still testing  negative? My sister keeps telling me that 5 days is a pretty long time when missing a period. This would be my first pregnancy, and she said that it might take my body longer to test positive with it being my first pregnancy? Wondering if this is true.

Been having some symptoms. Nauseous when I don't eat. Tired. My left nipple has little ammount of milk when it's squeezed (?!) Strong headaches, and cramping BUT These are all signs for me when I am about to get my period, as well. The migraines, fatigue, the cramping, acne, nauseous feeling (?) only thing I haven't gotten super bad is acne. 

Multiple days I've had cramps- thinking my period is about to come but still nothing. What do you guys think of all of this? Any advice , previous experiences where this happened to you, or any ideas would be much appreciated. 

Please help..