I know how you feel. Back when I was about 13 our house got broke into twice in 2 weeks. They came thru the doggie door into the garage, and then used a screw driver to get into the house door from the garage. We had a German Shepard dog, so we suspect it was someone we knew or had been over before. Also why the dog door was big enough for a thin guy to get into.
The first time they just took small stuff, jewelry and money. The second time, I walked in on them, didn't see them, but came in the door and heard a bunch of noise, ran out and to the neighbors to call police. They didn't get much the second time, but there was all kinds of stuff piled at the back door...no truck or van, I guess they were hauling it out the back door and down the alley way to some apartments behind our house...or it was our next door neighbors, they were seedy as well.
Anyway, no more dog door after that, and we got an alarm. Even an alarm that is not monitored will work. The thief will not know if the alarm is monitored or not, and even if it is, it will take the police 30 minutes to show up anyway from the time it goes off and the thieves know that. A full system can be built for about $500, get as many of the loudest speakers you can find, have them in the house as well as outside. Motion lights around the perimeter of the house also.
If someone wants in, they will get in no matter what you do, but a re-enforced steel door frame will prevent them from just kicking in the door like they did.
In our case the police did nothing, they did recover a camera at a pawn shop but that was it.
I would think they could have lifted prints on the stereo they left or door knobs, but a smart theif probably wears gloves.
If your state has a right to carry law, get a gun and don't leave home without it, I would not hesitate to kill anyone taking my property.