Take it from a guy who was on a Test/Tren cycle: Caber can fuck some people up who use it when they don't need it. Caber totally crashed my prolactin down 1/40th of the low range and now my dick doesn't stay hard. I'm pretty sure the crashed prolactin is why after reading a study that shows correlation. Men's Sexual Problems Linked to Low Prolactin Levels
My labs were taken two months ago and I still have a noodle that can't stay hard. I'll be getting bloods again next week for prolactin and thyroid function to see where I'm at. If my prolactin is still crashed I will be trying some domperidone in a desperate attempt to raise prolactin levels.
Any good dopamine agonist will crash Prolactin. I've had undetectable levels on Pramipexole. No issues. If anything, artificially suppressing Prolactin will increase libido.
Regarding naturally abnormally low Prolactin and sexual issues. If it's due to a problem in pituitary, then quite likely there will be many other hormone pathways mis-wired and low Prolactin itself is not the problem.
If you're off Cabergoline, your Prolactin most likely will be up. It is even not needed to wait that long for a new blood test - considering the half-life of Cabergoline a week should be enough. It can be assumed your Prolactin is not low anymore - you should evaluate other parameters that might have caused your issue.