Why is heavy bleeding on second day of periods?

You may be experiencing pain because of prostate infection or a UTI. I advise you to visit a doctor for proper diagnosis. He may suggest some antibiotics for your problem. Also, I suggest you take lot of liquids like cranberry juice etc. to remove the bacteria and toxins from the system. I hope this answer proved helpful. 

You may have vaginal infection, which manifests in the form of itching and white discharge. It is advisable to see a gynecologist that will identify and manage your condition in an amicable way. Also, it is recommended not to use any aggressive soaps or perfumes at the genital and follow good hygiene rules.

The possibility of pregnancy depends on the timing of sexual intercourse in relation to your menstrual cycle. Sperm can survive for several days, so conception is possible if you ovulated earlier than expected or have a shorter cycle. If you're concerned take a home pregnancy test after your missed period. 

Delay in periods can be caused due to many reasons like stress, hormonal changes, pregnancy, medications, etc. You need to consider your individual circumstances and consult with a doctor for a proper evaluation.