Pilot flying BE55 aircraft reported gear up landing while doing pattern work.

Narrative

I landed gear up at ZZZ. I was practicing takeoffs and landing to maintain currency. It was a very bumpy day. I successfully made two practice landings and was on the third one. The ground speed was high on downwind and I was managing with the props and throttle which was difficult in the chop. My usual procedure is to put the gear down first then flaps. Apparently I was distracted and did not put the gear down and continued the approach. On final I heard an intermittent warning horn which I thought was the stall warning. At the time I thought it was coming on because of the turbulence but in retrospect it must have been the gear warning. I should have gone around at that first indication. I landed and the plane skidded to a stop. In the future when flying a retractable plane I plan to leave the gear down during all pattern work. Also I plan to get recurrent training with a CFI and to study related safety webinars through the FAA Wings program and the American Bonanza Society. Check lists and GUMPS checks have always been part of my standard procedures but this time I failed the basics. Fortunately no one was hurt.