Storm-warning

I am a second career BSN who is 18 months into my nursing career, never worked in health care before. I graduated with honors. I am still at my first and only nursing job which is on the Heme/Onc unit at a major research hospital. 18 months in I find I am still struggling to master everything- from policies, to the way the hospital works, to skills, charting, and especially critical thinking. Every couple months I seem to make a mistake-some very minor, some quite substantial, fortunately for my pts and self nothing that has caused actual harm. But enough that I feel like I am always on the radar, and don't have a clean slate. When I have voiced my concerns to my educator and fellow nurses I am told in a nutshell, that Heme/Onc is the easiest place for newer nurses because you get a little bit of med surg and the rest is mostly chemo, blood, and nuetropenia complications. When things get too hairy, we send em to the ICU. I am struggling much more so than the traditional aged graduate nurses who were hired at the same time. They seem to have caught on no prob and don't appear to have made any mistakes, as well as excelling on the unit and now precepting students and serving on committees, etc. I seem to be the "old" black sheep who hasn't done enough to get fired but really isn't very good. Is Heme/Onc really considered "easy" in the hospital setting? I feel if I am struggling where I am at, then surely I will fail should I try to go to a different specialty that interest me-i.e med-surg or tele. As a second career person I do not have the luxury to hop around finding the right fit. I do love the onc population, but will this be all I can do, as everthing else is much harder? Will I even survive Heme/Onc as the months pass and I improve so slowly? Honest feedback and experiences would be appreciated.