The section bank is a jungle. Be prepared for the most insane questions, thinking, and an endless number of charts, figures, diagrams, and mechanisms to be presented to you.
Relax. Take a deep breath.
For the section bank, don't focus on how many you got right/wrong, or your overall percentage. Yes, there are pseudo-conversions on SDN and reddit that will say "if you get ___% on the Phys/Chem Section Bank you're going to get a 129 on the real test" that's all just correlation and guess work.
For the section bank, do the passages untimed. Its not uncommon to spend 20 to 30 minutes on a passage this way. Now, focus thoroughly on the passage and the questions. Read the passage word for word - you have no idea how many salient details are hidden away in there, and learning how to read looking for these clues is absolutely pertinent for the real MCAT. Once you master this and take your time solving the questions, you'll feel better because you've learned a lot, and you'll start to get more questions correct.
Also, while the section bank is generally harder than the real MCAT, expect anywhere between 2 to 5 section bank level difficulty passages on the actual MCAT phys/chem and bio/biochem sections.