Fertility Question?

I know that an irregular cycle can cause a decrease chance in trying to conceive. My cycles are crazy! It's like I will have a normal cycle for about 2-3 months then I'll skip some months. The longest time being 3 months. During that time I would cramp sometime throughout the day, everyday. But the cramps would be geared toward the left side toward the pelvis. Last week, my cycle lasted for about 4 days but it was kinda light. It was strange to me cause the first day it was thick, dark red and had a somewhat stringy discharge (like melted cheese pulled apart). Hopefully, I'll be going to the doctor soon and will inquire about PCOS. I'm not trying to conceive now, but would like to in the next 2-3 years. If the doctor gives me a shot that will jump start my cycle, I would like to get on birth control to regulate it but, when that time comes for trying to conceive will the doctor just switch medications that increase my chances of conceiving?