It does sound like the symtoms you are having are a side effect of the pill you are taking.
I am TTC #3 and each time before this one I had the same symptoms you are describing adn kept telling myself it just meant the insemination was working! And then
came!!!!
I will pray that I am wrong though and hopefully my prayers will get answered for you... I am only going by my experience and usually the heavy cramping means she is coming.