You were expecting your period 2 weeks ago (approximately around 15th of April). You had unprotected sex approximately around 1st of april, which falls approximately on the 15th or 16th day of your last menstruation
If your periods were regular, the day of contact falls during your ovulation period. So the chance for pregnancy
is more. Your pregnancy test has shown weak+ve. Repeat it after 2 or 3 days, you will get either +ve or -ve result and decide as per the result.
I wish you must get a result as per your wish.