hello welcome to hcm The pregnancy depends on various factors most importantly phase of amenorrhoea i.e. absence of periods. Since you have develop concern of pregnancy before it is unlikely according to history you are presenting as you say ‘ you have had a bleeding episode after the concerned coitus’ . But it is not killing the possibility of pregnancy . In my opinion you should first get a URINE PREGNANCY Kit and perform it. And then you must raise another question here about the issue with full details of your menses routine. A transvaginal ultrasound can be helpful but it wont be much effective since its really soon. TAKE CARE