Am I incompetent or is it a staffing vs. pt acuity issue?

Sorry this is long, but I would appreciate any input...........Please!

I work in a rural hospital on the general medical floor and there are nurses, mostly RN's, with differing years of experience from <1 yr to >20 years. The majority probably have an average of 1-7 years experience. I know I am a new nurse, just passsed my 1 yr anniversary, but I question my competency a lot. I work nights because I had trouble leaving on time doing 3-11 shifts and I occasionally still leave late when I do 12 hr night shifts. We do our staffing according to the census and not pt acuity. At times I feel the pt load is too much and/or the assignments are unsafe due to numbers &/or acuity. I am afraid to say something to the NM because I don't see others struggling like I sometimes do.....so it makes me think that it's just me & if I'm a 'squeeky wheel' I won't 'get the oil' but rather get replaced. I put my pt's needs first and usually have to finish charting after giving report. I still ask a lot of questions and ask for help when I'm falling behind, but I don't want to burden my co-workers. I DON'T like staying late or when people say "You're still here!" and the hospital is really watching overtime due to budget issues. I worry about the liability of being an RN, missing something in my assessment, not doing the right intervention, not calling the Dr. when needed or calling when it's not necessary (I had a Dr. get upset with me once for this) etc. and think my charting takes too long & is too detailed because of these worries.....how do you get past that? Does anyone staff according to the pt's acuity? And if so what kind of rating system do you use? I was told my facility used to staff by acuity, but that they found the nurses rating most of the pts high acuity so they could have smaller pt loads.