Without knowing anything about how the model was set up, there's no way of knowing what, if anything was wrong. Did you mechanically set up the plane when you assembled it so that both flaps and elevator are neutral when the bell crank is? Also, before flight, after attaching the lines and handle, did you make sure that the controls were neutral when the handle was? Some adjustment of the handle is typically required on a new model. If you did these, then about the only thing that could have put the plane into such behavior would be the pilot applying up elevator too early in the flight. With insufficient airspeed to maintain line tension, the model would certainly come in at you. Looping at takeoff is not an uncommon maneuver for new C/L pilots.
The Hangar 9 PT-19 is a pretty forgiving plane that is intended to help someone get into control line flying. If assembled per instructions with the recommended Evo 36 C/L engine, it would be unlikely to turn out so tail heavy that it would do what you describe without an out-of-trim condition, or over-control by the pilot. It is, however, very stunt capable and the Evo 36 has ample power to pull it along regardless of attitude.
As a former die-hard R/C Spadder, building a SPAD to re-acquaint yourself with the nuances of C/L flying is an excellent idea. However, keep it small. Little planes bounce a whole lot better than big ones and are a lot cheaper to build and repair. Once you've mastered a trainer and reacquainted yourself with C/L flying in general, go back to your repaired PT-19 and you'll have a whole lot more fun.
My first recommendation, if you have access to coroplast, would bee the Man-Winn trainer
http://www.balsabeavers.ca/begginers_page.htm
This little plane is virtually indestructable. It has minimal parts and can easily be assembled in a weekend. Note that it uses a Cox .049 engine. Flown over grass it can take an extraordinary amount of abuse. You can get a Cox engine at
http://coxengines.ca/ Get 1/2 A fuel (20-25% nitro) at the LHS or from Tower and add castor oil to get to about 20% total lube. Tower sells Klotz castor oil too and it works just fine. Modern R/C glow fuels don't have enough oil for the Cox's iron piston, so keep this in mind if you decide to go this route.
Another great option is the Osborne platter at the Aeromaniacs web site. It's made from paper-backed foam board, that you can get just about any place that sells office supplies, and a few pieces of wood. It's not as tough as the Man-Winn Trainer, but is a lot lighter and flies better, IMHO. It's also an easy build, but unlike the Man-Winn, needs a painted finish on it. If you're not keen on that, then find a piece of coroplast and do the Man-Winn. If interested, here's where you get the info on the platter.
http://www.aeromaniacs.com/Platterins.html
Above all, don't get discouraged. C/L flying is neither intuitive nor easy. You are never more than the length of your lines away from terra firma, so things tend to happen fast and violently when they go wrong. I had a lot less trouble learning to fly R/C with a buddy box than re-learning C/L. Since I had coro, I built the Man-Winn Trainer and beat the snot out of it. My poor little Cox Sure Start ate a ton of grass, but kept on ticking. I use my trainer now to let anyone who cares to try their hand at C/L flying. Have also built a Coro-Platter (on Aeromaniacs as well), which is as tough as the Man-Winn because it's made of coroplast. That one can be made from a discarded (or misappropriated) election campaign sign with material to spare.
Don't trouble yourself with landing gear on a 1/2 A plane if you decide to go this route. The wheels are so small they won't roll on grass anyway and just get bent up when you try to land. Just have your buddy give you a hand launch.
Good Luck!
Chuck