Ok, with my 3rd pregnancy, i did not know i was pregnant until i was about 12 weeks!! Seriously. I owned my own business and was crazy busy and i did not keep track of my cycles.
Anyway, my husband and i went to a baseball game one day and I had to walk up a zillion stairs and my thighs BURNED so bad. I said to him that only happens when I am pregnant. I went into the bathroom after the trip up the mountain of stairs, looked in the mirror and instantly "knew" I was pregnant! I was glowing. really. It was kind of neat.
Other than the burning legs, and actually glowing
I had absolutely no symptoms to speak of the entire 1st trimester. I did start craving Mexican food right after that and I normally hate Mexican food. And shortly after that my belly size quickly made up for my lack of noticing - I got huge fast.
I hope this helps.
BTW, I am in the lack of symptoms this time as well, so the reassuring stories help me too even though i have my own to tell.