If you have been sick and took cough meds it can cause alot of discharge.
I agree with science teacher. Also, the discharge and aching you had could be a sign that you ovulated at that point...and if so, you might get AF about two weeks after that.
Basically, the discharge changes throughout the cycle, and it's more abundant, clear and stretchy right around ovulation. And most women ovulate about 12-16 days before their next period. As for the aching, if it seems to be from the ovary-region, it could be ovulation cramps. Many women get that around ovulation.
Take care!
You may not have ovulated at all last month (so no period). Or you may have ovulated later than normal and your period will just be later.