Normally if you have bright red fresh blood after a bowel motion it comes from haemorrhoids.
These are like varicose veins and get irritated with the bowel motion and consequently bleed.
If they are painful and bad you can get a prescription cream to make them smaller. Over the counter creams don't make much of a difference in size, but contain a local anaesthetic that can make them feel better.
Also having a diet high in water/fluids and fibre will help keep your bowel motions soft as constipation will make it worse.
Also occasionally constipation will cause anal fissues as the hard bits of fecal matter pass and these can bleed.
If you have dark black bowel motions this can indicate bleeding higher up the gastrointestinal tract.
But it's probably in your best interest to see a doctor and have an exam. It's nothing they haven't seen before and a bit of embarrassment now is better than something really bad in the future.
I would wait to see how much passes first. If it stops with a few minutes you will be fine but be sure to make a doctor app. lots of time rectal bleeding comes from constipation ( doesnt sound like you have that ) or hemmoroids. If it continues and you feel weak or dizzy then you will need urgent care to get it checked out. Just monitor it. Many cases of rectal bleeding are minimal and stop on there own ( considering if they are bright red drops and only a few ) but in more severe cases you would be passing a few spoonfuls of blood. hope this helps