Faint line, light spotting and major cramps

This morning I had a faint line, 3 days late for AF, but an hour or so after I had intense back ache and pretty intense cramping, a light red/pink discharge only when I wipe for the last 2 hours. It feels like AF....but normally I start a flow with a bang...any input? I finally got excited about a possible positive and now I'm struggling....I'm finding it hard to not go to the br every 5 seconds to see if the flow is increased.