No actually u can only be that far along bc when I went to the doc n found out I was preg after missin three periods she said that she didnt think I was as far as (according to lmp)bc of my preg test wasnt that dark so she said I could only be a couple weeks along but what she also said was I could of still gotten preg any time during those months I had no period bc just bc I wasnt having a period doesnt mean I was not ovulating .... So then I had a dr appt today and he checked me n everything then asked when my last period was and said he didnt think I was 15 weeks bc my uterus didnt feel like it and he said he would try to find the heartbeat bc u can hear that at 12 weeks and so he tried but couldnt find it... So he doesnt think im that far either. .... And me I took alot of test after I missed the first period then more after I missed the second and all came up neg.... So prolly conceived during the time I didnt have a period .... Cuz liek she said just cuz ur not having periods doesnt mean ur not ovulating so I hope this helps ya!! Good luck

I am pergnant for the second time without a period. So yes it is enitrely possible. I would trust the blood test for how far along you are. Go and get an ultrasound done if you are worried about the heart beat.. And remember to relax it's the best thing you can do for your baby. I hope everything goes okay.
Ps sounds like our due dates would be around the same time. But I am 12 weeks, and i'm due in july, but I conceived in early oct too.