Hello I'm 18. I Got My First Period When I

Hello I'm 18. I got my first period when I was 11 going on 12. However, it has always been irregular for all this time. Sometimes I go up to 4-5 months without a period. As of now i have not had my period in about 3 months but lately I keep getting what I believe is cervical mucus that is brown in color. I am really quite confused on what is happening with my body. I am not sure if it is normal to have cervical mucus that is dark brown. Do you have any ideas?