I was a PV retaker in my class out of 18 a couple of weeks ago, nearly a washout myself! In my class, 3 of us had to retake and out of those three, one guy didn't make it. My nerves really got to me in the first run and I completely bombed it. I was shaky and lacked confidence, and I couldn't concentrate at all. I let the problem control me instead of the other way around. I've gotta say it was probably one of the worst days of my life and an experience I would like to never again repeat!
My advice is to try to stay calm during your PV and work on focusing on running a good problem, and passing it on the first try. Most people do pass the first time around, but usually a few students in every class (like myself) struggle with it. If you do have to retake don't panic, just go through with it and do your best on the 2nd try, no matter how much you feel like quitting during your practice problems! My instructor was telling me that some students simply have to get their nervous energy out the first time and just take it again, as what seemed to be the case with me.
I definitely recommend studying as much as you can and working with people in your class, make sure your phraseology is tight and your traffic search is quick and accurate. Know your airspace inside and out! Also get your eyes on your scope and away from your strips after you've conducted your initial traffic search/aircraft analysis, it's what saved me the 2nd time around.
All in all, work hard and don't give up no matter how tough it seems, abide by all the rules, make friends with your classmates, and believe in yourself. I am living proof that almost anyone can make it through if they keep trying...so good luck! Any questions feel free to PM me and I'll try my best to answer them!