I'm 6 days away from a missed period, blood test came out 6 mui of hcg is this number ok, for being 6 days before my missed period?

Who knows?: You are trying mighty hard. To be testing so early is a bit of a stressor that will not change outcome. It sounds appropriate in that the cells have just implanted. Miscarriage rates are hard to quantify at this stage, it's thought that a significant number of implantations don't make it and the woman never knows, she just has a period. It likely won't be u and 6 sounds fine at day 22 of cycle.