Hello dear
I understand your concern
There is no chance of the
pregnancy as you did sex on the 24th day of the cycle and it is completely safe period of the cycle.
During this time, there is no ovulation occurs then no chance of the fertilization
Ovarian cyst can cause
hormonal imbalance and cause difficulty in become pregnant.
But once ovarian cyst will resolves and hormonal imbalance has been corrected, you will become the pregnant.
You can take prontogest: it will help to resolves the cyst and correct hormonal imbalance
Other drug like birth control pill,
metformin can be used.
Blood HCG and USG are the best tool to diagnose the pregnancy.
Both are negative in your case
So do not worry there is no chance of pregnancy.
Avoid
stress, take healthy diet, drink plenty of water, do regular exercise
Hope this may help you
Best regards
Dr. Sagar