Frustrated!

I am beyond frustrated. I am 18dpo. Or what I think. My cycle has been very scattered in previous months. I thought I was starting to get regular. Af has not shown her face. I took a test on Tuesday and it was bfn. I am going to the store now to get a first response. I don't take the opk. My husband says it takes the fun out of it. Which I understand but it makes planning a pregnancy that much harder. So there is a possibility I ovulated earlier or later than what I think. What do you guys think the chances of me being pregnant are? Has anyone been through this and still had a bfp?