Hi there,
Your period may be delayed because of stress and also not getting enough rest. If all pregnancy tests come up negative after you have already missed your period, then you're definitely not pregnant. The spotting is a sign that your period is trying to start, but your hormones may not be balanced right now to give you a full-blown period. Relax and get more sleep. If your period doesn't regulate itself out in the following months, I'd recommend seeing seeing a gynecologist.