Ay mama, that sounds like a stressful situation talaga! Spotting followed by a negative PT and then a regular period two weeks later is usually just your body doing its thing, hormones can be unpredictable sometimes, lalo na kung may stress or changes kang naranasan, but since you're worried, I'd really suggest checking in with your OB/GYN para ma-confirm at ma-ease ang mind mo, kasi they can check your hormone levels or if may iba pang reason. One of my friends had something similar and it turned out normal lang, pero much better na siya na-clear ng doctor mismo, kaya peace of mind talaga! Hugs, mommy.