Here's my story and I think this is what's happening to the OP. My first Heli was a Chinese made cheapo that had the plastic guards on the main rotor and I never got that one off the ground, it broke the first time I tried to fly it. Figuring it was the cheapness of the aircraft, I bought a Sabre FP Heli at Hobby People. I was never able to get it off the ground as it would skip to the left and usually fall over and die; $150.00 plus tax doen the drain. Then I learned about the Blade Coaxial CX. I bought one and bent 2 fly bars, burnt out a 4 in 1 unit and had to replace the main shaft twice before I was able to really fly the thing. Finally though, I pretty much became an expert witht he Blade CX. When the mCX came out I was intrigued by its size to I bought one and had more fun with it than with the CX. The mCX really taught me control in tight spaces and the absolute need for finesse with the control sticks.

I think this is an abolute necessity for a beginner and think that the OP made a critical mistake in trying to get into RC Helis; just like I did at first. I believe that knowing the dynamics of heli flight is important, but not as important as knowing that slight movement of input controls are everything in this hobby. I flew the mCX for about 12 months before I got to be an expert with that. Then I heard about the mSR, Because I was able to learn stick control and dynamics to a degree with the mCX, I flew the mSR right out of the box. Ok, it took a great deal more finesse on the sticks and a couple of close calls to get that into my head, but, after 2 battery packs I am flying this little guy like a pro.

A couple of days ago I was at my local Hobby Town and saw the SR 120 BNF. I bought one and had her flying  the minute I got her home. Because of her size, the tendency to skid to the left is more pronounced, but that is where my previous experience with the mSR came in. So far I have only flown the 120 SR in the house, but I know it will be more fun outside. So, my advice, don't jump into RC Heli cold. You need to work into it or devote a lot of time and frustration to the hobby. I too am an RC car\truck guy who likes fast nitro stuff, but, Helis are much more complicated and difficult to master.