Failed experiments with no results…

Hi everyone.

I’m currently finishing my first year of my PhD in Exercise Science, specifically, molecular physiology. I have been having trouble getting results trying to measure proteins using the westernblot method for my second research unit (right before I have to submit a thesis proposal). I haven’t been able to determine if the technique is not done properly or if I screwed up during the cell culture. My supervisor is never in the lab and he’s hard to get a hold of. I’ve been getting help from the lab manager, who says that it seems that I am not the problem, yet he has no real explanation for what is going on.

My question is, when do you know when to give up with a technique/method and just move on to the next experiment? I have tried the damned experiments about 3 times from the culture stage and 4-5 times for the western blot stage.
I feel like I won’t get results and I’m gonna fail everything.

Anyone with experience in this kind of thing or situation?