How far along am I? Help!

possibly a stupid question but I'm really struggling to work out how far along I am. My last cycle was very strange. My period started on the 1st January 2016 and lasted to the 6th. I then ovulated and had sex on the 7th (this was when we must of conceived, either this day or just after) because of my very early ovulation day a lot of apps don't really work out the right amount of weeks pregnant I am. I did a clear blue digi today and it said 1-2 weeks, but is this since implantation? so therefore it could be 3 weeks? should I go from the 7th as a conception day and ignore he whole first day of last period thing? I'm very confused. any help is appreciated.