I absolutely agree that you should have had introduction to critical care class and add additional classes as your orientation progresses.
There appears to be a mismatch with your preceptor. Investigate if a different preceptor is available(I know, you don't want to step on toes-but you need a supportive preceptor) Is it possible that the sensory overload that your experiencing is sensitizing you and when instruction given, it feels as your being scolded? If you haven't, purchase pocket book guides on critical care to guide you. The American assoc. of critical care has many references and apps that you can purchase. I'm an experienced critical care nurse and I always carry my palm pilot to research new meds, check on interactions, obtain information on critical care(sepsis bundles), etc.. Many of the companies that produce the equipment you use have education on their web sites.
When you enter a patient's room utilize ABC+Ds: airwary,breathing, circulation and drugs(IV fluids, IV pressors present) to start with. There are some free online articles/classes that you can take to help yourself build the knowledge you need,but-------You need an interpreter on your side to help you utilize what you are learning. Find out from the staff members which nurses they go to for information/analysis of information. Get somebody to support you.