Im in need of some explications. From what I understand , to calculate how far along one is in pregnancy, you calculate from the first day of you last period. My last period was dec 30th which on my calculations means Im 5 weeks. The <a href="https://play.google.com/store/apps/details?id=com.glow.android">glow app</a> says 5 weeks and one day but the glow <a href="https://play.google.com/store/apps/details?id=com.glow.android.nurture">nurture</a> app says 4 weeks and 3 days ?! Does anyone know what is right ?