Discharge after sex for a female (a tad bit of blood, mucous and other stuff) is normal. It doesn't have to be related to pregnancy or the period. http://www.medhelp.org/posts/Womens-Health/Discharge-after-sexis-this-normal/show/28184?forums=forums with lots of posts of the similar. Blood, spotting is possible for a virgin when the hymen is broken. I assume that since you had sex this your first time that your hymen has been broken. Of course in our modern times young girls tend to rip/break their hymens playing sports, riding bikes and other things. Then there are partial rips/breaks due to sports which may result in no pain during intercourse but the remainder is torn leading to a little blood. You are upset in the belly because you are stressing out about the potential of being pregnant. You are scared, fear leads to many physical symptoms, upset tummy is one, for women it can also lead to late or premature menstruation. Fear is a form of stress. Stress is bad in large quantities. If you used protection like a condom, then the chances of being pregnant are less than 2% unless the condom broke. If you used 'the Pill', your chances are around or less than 1% depending on what form of the pill you used. While it is statistically possible that you are pregnant, it is also statistically possible that your first pregnancy will end in miscarriage. It is thought that around 80% of first pregnancies naturally abort during the first month with most women only having a heavier than normal flow. Of course in your case you have stress going on which most likely will be the cause of a heavier than normal flow if you have one this time around. So all of these odds, all of these words are to basically reassure you that you are not experiencing pregnancy symptoms and that you will be just fine.