Positive OPK and HPT????

Ok, so I have an irregular cycle and last month I was a couple of days later than usual. (36 days, normally 34ish) So I took a couple of tests and they came out negative. I got what I assumed was my period, then last weekend on what should have been cycle day 11, I noticed some signs that I might be ovulating. I took an opk and it was positive. I've had positive OPKs every day for the last week. I'm currently on what should be cycle day 18 and I have been so nauseous the last four days it's crazy. I just took a opk and a hpt and they are both positive! I'm confused and scared. Has this happened to anyone else?