What the heck is wrong with me..?

For the last 2 months I've had a period every 10-20 days. All of a sudden I'm having very irregular periods. I don't know why. This has never been an issue for me. My cycles have been 30-35 days my whole life. I went to my regular doctor. She couldn't find anything wrong and advised me to see my obgyn so I have an appointment for Friday. This is driving me nuts. I was baby #2 so bad and with this ridiculous cycle its not going to happen? Thoughts? Opinions? Advice? Similar situation? Anything?