Dodgy ovulation tests!! Grrr!!

Hi ladies I bought my usual internet cheapie OPK's and normally I don't have any problems with them but this month they just don't seem to be doing anything :( the control line is coming up but not that dark & there is hardly a faint second line and I'm due to ovulated in 48 hours!! Thinking I may have a crap batch!! Anyone else had this happen with internet cheapies?? Xx