BFP! But still confused!?

Rebecca • Hoping for a baby boy 🤞🏼💙

​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​So my last period was on December 2nd 2017. I missed my period that was due the last week of December and so i took three different tests that week after i missed my period but they were all negative. Now that were into January i still hadnt got my period so i just thought my cycle was messed up but this morning i took this test just because and i got a positive ! My only question is how far along am i really? And why did i get negative results ?