I second (or third or whatever!) the suggestion of finding a training club. Even if you can't afford or don't have enough time to commit to an entire class series, just going and talking to a trainer may gain you some valuable insight.
RE: cars/passing dogs. Olive does that all the time. I have been working with her and using two methods that have shown to be effective. One, I just keep walking! I keep my head up, I don't change my pace, and I don't say anything to her when she reacts to the cars. I just keep right on going. She has started to figure out that I'm not reacting to the car, so maybe she doesn't need to react either.
The other technique I've been using, for cars/dogs/people/shadows (she is a huge shadow-chaser), is to step down on her leash and just wait her out. I step down about two feet out from her collar, just enough so she'll feel the slack go out but not anywhere near enough to force her to move. I stand on the leash and wait until she a) puts herself in a down (which at first I used a command for, and now she knows she has to do it), and b) she chills out. I put her at chilled out when she start to sniff the breeze, lay on her side, etc; basically when the tension is gone. By standing on the leash, she doesn't get any of my stress or anxiety channeling through to her. While I wait her out, I ignore her. I call it my doggie meditation time.
She still goes berserk when I have her out, but she is getting much better. Your dog will, too. It can take a lot of time and patience. If you know you are going to lose your cool (and I can relate!), work with your dog in smaller time increments. If you study for school at home, study for 45 minutes, then take 5 minutes with your dog. Pick just two or three simple things to work on each week and work only on those. Doing too much at once can be frustrating for you and your dog.
If your parents are receptive, maybe they can help with training. Clicker training might be an option. You could just have them do hand contacts ("touch"). Builds a relationship between them and your dog, and will help your dog become more attentive and responsive to them.
RE: cars/passing dogs. Olive does that all the time. I have been working with her and using two methods that have shown to be effective. One, I just keep walking! I keep my head up, I don't change my pace, and I don't say anything to her when she reacts to the cars. I just keep right on going. She has started to figure out that I'm not reacting to the car, so maybe she doesn't need to react either.
The other technique I've been using, for cars/dogs/people/shadows (she is a huge shadow-chaser), is to step down on her leash and just wait her out. I step down about two feet out from her collar, just enough so she'll feel the slack go out but not anywhere near enough to force her to move. I stand on the leash and wait until she a) puts herself in a down (which at first I used a command for, and now she knows she has to do it), and b) she chills out. I put her at chilled out when she start to sniff the breeze, lay on her side, etc; basically when the tension is gone. By standing on the leash, she doesn't get any of my stress or anxiety channeling through to her. While I wait her out, I ignore her. I call it my doggie meditation time.

She still goes berserk when I have her out, but she is getting much better. Your dog will, too. It can take a lot of time and patience. If you know you are going to lose your cool (and I can relate!), work with your dog in smaller time increments. If you study for school at home, study for 45 minutes, then take 5 minutes with your dog. Pick just two or three simple things to work on each week and work only on those. Doing too much at once can be frustrating for you and your dog.
If your parents are receptive, maybe they can help with training. Clicker training might be an option. You could just have them do hand contacts ("touch"). Builds a relationship between them and your dog, and will help your dog become more attentive and responsive to them.