This sounds similar to what happend to me a few months ago,
i had so many signs, my boobs grew, there were blue veins all over them and the areola, nipples were darker, I had gone off certain foods, I was incredibly tired, a pooch appeared and I had 2 "peroids" that were more torture than anything else, just enough to make me wear a pad but not really enough if you knwo what I mean, with this I had cramps and allt he fun stuff.
I did several tests all neg and eventually had a blood test done as I was getting pain with it which was unlike me. All came back neg, hgc levels were below 5.. So not pregnant.
My dr is a as and said would take it further to see why all the of this had happened, but did nothing.
I figured if they were wrong time would tell.. And if I were I woudl be 18 weeks by now.. And my belly is nice and flat still so I guess they were right all along! But the veins are only just dissapearing, there are still a few visable but the rest have gone back to hiding!
Keep a open mind, dont let your self think you def are cause if you arnt you will be dissapointed.. And if you are.. You will be double happy!!
Good luck!