Advice with Clomid

Hi, 

Does anyone have any advice experience taking Clomid? I've been trying to conceive for the last two and a half years and I'm currently on my 7th cycle of Clomid 50mg taken days 2-6. 

My periods have been all over the place since the birth of my son in 2011 who was conceived without any problems on our first attempt. My cycle could be anything from 29-38 days. My blood tests showed I wasn't ovulating every month hence the Clomid. The last 6 cycles have been around 31 days where as this one is 37 days so far. I'm moody (although this could be due to the waiting etc), had cramps, sore boobs and today ive had the normal discharge i get before my period but still no af but all the signs are there. I know its possible i could be pregnant but I dont want to do a test as im fed up with all the negative ones done in the past and I don't trust my body as my cycles have been long before. Should I wait till Friday to test as then my cycle would be 40 days. 

Has anyone else had experience with there cycle lengthing Or being this long after taking Clomid? Or any advice in general as the waiting is driving me nuts! 

Thanks