It is not a question of 50 days from lwast period, especially when we don't know anything about the pattern of the cycle.  Calculation becomes difficult. My feeling is that you are interested in this pregnancy. If that be so, please don't be in a hurry to get confirmation. You may do urine test about a month after sexual contact if you don't get your periods.

Yes You aren't pregnant

if both are neg pregnancy unlikely

Hi If u hv irregular period n u are planning a pregnancy,  consult a doctor U myt not be ovulating or u myt hv dum other problem thyroid , prolactin , which is hindering ur period n also conception .

Yes u can check now Urine sample ... anytime of the day