Gave birth 4 weeks ago bleeding nearly stopped then day later it was bright red again and I'm not breast feeding is it normal

Yes, it can be normal. It may be that you overdid it. Sometimes a return to red bleeding, after it has subsided, is your body's way of letting you know that you are trying to do too much too soon.

Take it easy for a couple of days and see what happens. Some discharge in the first 6 weeks is common. If it were to be continuous, you would want to let your doctor or midwife be aware.