Do you see anything???

I took another test just to check, because I was due for AF Dec 11, and it came the 13th, first day really really light, day 2 was darker n then it was gone...by the 15th had nothing at all, the 16th had light spotting light pink the 17th spotting again but only once , and the 18th when I went to bathroom light pink, kind of brownish looking... So I was really confussed... I'm 31.5 yrs old and this when it happens would be #4. My youngest is almost 9... All boys... And how would I know I'm ovualating when it's that time with all this happening. I've never had to try to conceive before but now this past April, my husband had a vasectomy reversal and it's all new n different to me... Any and all suggestions or experience is welcome...thank you