LH question...

justine
So this is my 1st month using opk's that are not digital and so far im on cd22 and i had a positive opk on cd 16 and cd 17 with a 32 day cycle so obviously after cd 17 the opk's got a lot fainter but now they r starting to darken again. The only reason im doing more opk's is just to see my cycle pattern before i switch to htp's but my question is is it normal for the opk's to get darker again before a bfp or af? Im just really curious if ppl who have gotten their bfp's had another LH surge after they o'd?