So making your problem graphicaly i understand the next:
Sat May 17 lost viginity --- Sun May 18 day that you pweriod should had begun --- from that day till Thu May 27 you had intercourse in 4 more times --- Wen May 28 strange bleeding and pink discharge (10 days past due your expected mestrual date) --- Today May 30 stilll not a normal bleed and a lot of cramps.
I does not seems to be that it is an implantation bleeding. Taking for granted that you are a very regular woman your possibilities of pregnancy should be low. More information is needed of course, like:
- is this your first irregular period of the year?
- which is your regular rythm?
- did you used any kind of emergency contraceptive?
I agree with Butrflynet you can be causing it with friction. And her articles are quite accurate. However the must wise thing to do is performing a pregnancy test.
In this case a serum pregnancy test will be the best options, since blood in urine can cause false negatives.
Stress and fear can be causing your period anormality, but also the emotion the strong feelings of anxiety related to the first sexual intercourse can. Also the high levels of testosterone found in normal male semen can disrupt normal endocervical and endometrial secretions and cause strange discharges.
Look for a doctor of your trust. The best are those who are willing to explain every question in a easy manner using common language. I highly recommend to ask someone you know that has a child with asthma, that disease is really troublesome and they allways happen to know a lot of doctors.
Also once you past this situation i highly recommend using an hormonal implant as a contraceptive method. Also pills are a good choice. Must countries provide contraceptives for free.