Still no AF and still no BPF.....advice pls?

This is driving me nuts. My cycle is not regular by any means but my cycle is usually on the short side 24-26 days....last month 31 days and now this month I am going on 35 days. I have been using OPKS and only have gotten 1 positive in the 4 months I have been using them. I feel like this is consuming my mind and every morning I take a dollar store hpt only to get a negative. At what point to I go to the Dr for blood work or is there something else I should do?