Don't try to guess how far you are... I thought I had a period and im not sure if it was or if it was implantation but when I went for my first check up the Dr was INSISTENT that I was not even 4 weeks BC of my LMP . I demanded an ultrasound BC my girl friend who had came with me has 4 children 3 of whom she got her period for the first 3 months. The ultrasound showed and confirmed that I was actually 5w1d.4I know that's not a HUGE difference and you are only looking for an estimation but if I were you I would get in with a doc Or midwife ASAP just so you can actually know what's going on. Also you wanna get started on prenatal vitamins and take care of that Lil bean