Thinking of backing out..

Well the cramping has started and I am so bloated..I know my period is starting and I am suppose to stop taking my BCP pills on Saturday and I have my baseline ultrasound on Friday! My body is kind of doing its own thing again!! I don't know I am thinking of calling off the IVF even before it really starts!! I am so scared to be disappointed! I am so aggravated!! I just know my period is going to start early, I know it's sounds silly but that's what happen last cycle! I don't know but I am so tired. How do you turn off the faucet of wanting to be a mom??..