When should I test???

Faye • Currently taking 3mg Bromocriptine for high prolactin levels, 1000mg metformin a day for PCOS. 1 ectopic pregnancy ❤️
So today it has been 31 days since my previous AF.
I recently started medication to lower my prolactin levels which has helped sort out my cycles and ovulation.
It is hard to know how long my cycles are just yet. I am struggling to know when to take a HPT
My last AF was 28/02/16
I keep putting off taking a test, because I enjoy believing and treating my body like I am pregnant, before getting the disappointing BFN :(
What are your thoughts when should I test??? X