Please help. Im desperate .

So my periods are irregular. Every other month. Idk when I ovulate ... Opks are a waste of money. Glow says I ovulate 3 weeks after my period (ovulated a few days ago basically says glow) and I thought it was the first week or 2 after your period you ovulate. Has this happened to anyone? Does anyone else have periods like me? And did anyone get pregnant? Any help please.

& No I'm not or ever was on birth control etc