I had sex a few days before menstruation, and now I always want to go to the toilet, and I have pain

Don't be nervous, just don't scratch after a mosquito bite.

Sperm residue, sperm will have a peculiar smell if it stays for a long time, and go to the toilet to remove residual sperm, so there is a peculiar smell.

This is a normal phenomenon, that is, it is caused by menstruation, and it is not excluded that the blood in the discharge is mostly caused by vaginal inflammation or cervical inflammation, etc., you can wait for the menstrual situation and the duration of the blood in the secretion. If there is blood in the discharge for a long time, it is necessary to check the discharge and cervix in time to confirm the diagnosis, and then treat it accordingly. If you don't have a period after your period, you don't have to worry about it.

Did you have a relationship with your daughter-in-law when you came back from drinking and went to the toilet, and was there a direct connection? I don't quite understand.

Oozing blood at night, if there is no inflammation, it is fine, if there is inflammation, anti-inflammatory treatment is required.