Dates need advice please ladies x

ent from light pink spotting to brown this was for 5 days now today I have nothing! I still have my fingers crossed as went for a scan could only see a sac tech said I'm either earlier than I thought or the pregnancy hasn't progressed. I'm still getting 3+ on clear blue so I presume that's a good thing. Also I based my dates on 28 day cycle and I looked at my period tracker and my average cycle is 33 days. Does anyone know if that could make a difference to my dates