That beautiful laminar flow wing has very high drag at high angles of attack. The M20J does not accelerate very briskly and attempting to pull it off the runway before it is ready will result in vastly diminished performance. if the stall warning was sounding continuously from liftoff, that says a lot.
Within 25 hours after buying my Mooney I experienced this first hand. I had taken off fine from an airport with a full load of passengers, luggage and fuel -- within 50 lbs. of max weight and well within the CG envelope. Experienced no problems. Flew for 2 hours to my destination, came in to land, didn't like how I was lining up and elected to do a go around. Added full power, flaps to take-off and could not climb out of ground effect. Cleared the end of the runway about wings length above the surface, nose high, stall chirping. It took every bit of my will power to push the nose over and lose about 15 feet of altitude to gain speed. After the nose was down, she accelerated rapidly and I was able to climb.
After the obligatory undergarment change, I spent time with my instructor and went through the scenario. He explained the concept of being behind the power curve, the loss of wing efficiency due to the high angle of attack, that the density altitude was about 1k above field elevation, that this was my real first trip with the plane loaded and an expectation that it would perform as it always did. It didn't. That event was sobering to me and enlightened me that what we do can have a thin margin of error.