OPKs ??

Tori • Angel Momma. Bentlee&Braxton 10.12.16 Growing our rainbow ❤️
I used a clear blue advanced digital OPK this afternoon results were positive, blinking smiley face. 
Few hours later took a cheapie strip OPK results where clearly negative, nearly no test line at all. 
Has anyone ever dealt with this before? I've been using OPKs for around three cycles now and have got nothing but confusion. Last cycle I had extremely positive results for 6 days, tested a week later, still positive. Now I'm having this issue. So just looking for advice.