Ovulation tests?

I have a lengthy cycle so my doctor told me to start taking my ovulation tests around day 14-ish.. So I started on the 15th day and it came back positive.. And again for the 3 days after. So today was my fourth positive in a row. I read the LH surge should only last a day normally, sometimes two, and rarely three days. I took a pregnancy test because I read that it could detect that as well but that came back negative. There weren't many answers about this when I googled it, so has anyone ever had anything similar happen to them? If so, what came of it??