Opks and no period

Does anyone who hasnt had their period been using OPKs? I have been tracking off and on for a month or so and I've never had so much as a second line show however last week I felt funny (horny lol sorry) had ALOT of ewcm so thought I would check. First two days nothing at all again but 3rd day in the morning I had an almost positive opk! Tried that afternoon but no second line again! Just wondering if I will get my period now? Should note I had sex on the 2nd night