Missed period

Usually my period is quite regular, usual cycle is 29 days. I’ve missed my period for 2.5 weeks now (cycle 51days now), i had brown discharge and light spotting during the time of my supposedly period. Been feeling fatigue and nausea. I’ve tested PT a few times but it is negative. Feeling sad and disappointed from the results. Hoping i could have a little bun soon, but could I still be pregnant? Anyone has tested negative even missing period for few weeks but was indeed pregnant?