Looking for advice

So long story, my periods haven’t been regular. Last one was 68 days. I’m on day 52 right now. I tested on 42 with bfn. On a whim decided to take an opk this morning. Well it was as dark as possible. I already got a positive opk a few weeks ago. Is this the opk picking up hcg? If I’m 4 weeks past ovulation, it could pick up on it. I’m not sure if I should keep taking these to see if they stay dark, or go get some pregnancy tests now. I don’t want to get my hopes up. Please only positive comments, it’s been over 2.5 years of trying and this would be the perfect Christmas present.