Honestly, it's only been 4 months. Most doctor's won't even talk to you about fertility treatments or anything of that sort until you've been trying for a year, at your age. If you were 35, they'd start doing tests and such after 6 months of trying.
We got pregnant with our first son while using a condom. It broke, and he appeared, lol. But with our second son, it took us 2 1/2 years.
My advice to you, for now, is quit "trying". Your cycles are wonky, so get that straightened out. Your dr. might be able to give you Provera.
If you absolutely want to go nutso with trying, then the best thing to do is sign up on Fertiltyfriend.com. It's a free website and you can keep track of your ovulation and cycles there.
They will teach you how to do PROPER temping, how to check for cervical mucus (which is in abundance when you ovulate, and a GOOD thing), tips on how to help the process along, it will tell you when you've ovulated, if you've hit your days needed, etc.
There are also message boards that you can chat with other TTCer's about your struggles. But like I said, it's only been 4 months. That's nothing. You're just putting more pressure on yourself right now. Which can contribute to the wonkiness in your periods. Stress will throw you all off. So have a glass of wine, relax, and have FUN!
If you want to ask me more questions, please feel free to email me at ____@____.com. I did the charting for a year and a half.