Dampry I had results of 14 with my first blood test at 5weeks and even though it went up for another week it was never what it should have been and unfortunately ended in m/c at 6weeks. I to had a lot of cramps but I had bleeds as well so hopefully your lack of any bleeding is a good sign.
We did ivf so we knew exact dates. Is there a chance you ovulated a bit later?
In saying that I read some stories of where it went onto a successful pregnancy. I hope your next blood test brings you a huge jump and everything is ok. Xo