Hello Amanda and welcome to HCM.
Thank you for your query.
First of all symptoms like increased libido, sore breasts, etc; are due to your hormones. These hormones are normally elevated around or during your period. So, you could be experiencing this because of an approaching period. A delay in periods can be caused by many normal factors like sexual intercourse,
stress, etc.
If you wish to rule out
pregnancy, the best time to conduct a urine pregnancy test would be 20 days after your last sexual intercourse or on the first or second day of a missed period. An early morning urine sample would be most accurate in yielding a result. This can be repeated 2-3 times, in such a manner, to conclude on a particular result.
The presence of a discharge brings up the possibility of infections. Infections can also result in a delayed period in a woman who has otherwise not experienced irregularity in her periods. You will have to rule this out as well. Please visit a doctor to do so.
I doubt this could be cancer, and is most probably one of the above stated reasons. So do not worry, and visit your doctor at the earliest to return to normal health.
I hope I have succeeded in providing the information you were looking for. Please feel free to write back to me for any further clarifications. I would gladly help you.
Best wishes.