I had shingles last month and i havent gotten my period in a month and a half, could i be pregnant or stress?

If anyone is out there and can help please respond. I have noone at home i can talk to and i truly need advice. Last month I had shingles for about 3-4 weeks and ever since then i havent gotten my period, it been a month and a half and my period has never came late since i began my menstrual cycle. I had taken a test about 3 weeks ago and it came back negative. Im really scared to death that the test i took came up wrong and i am pregnant. But i also read stress can delay your period, i started to beleive this then last night brown discharge appeared and im terrifiedd. PLEASE SOMEONE HELP ME I REALLLLLY NEED ADVICE