Is it safe to breastfed a baby even if you are taking paracetamol and had a headache?

No you should talk to your doctor first about any medications that you can take. As of currently it's unknown what harm can be done to a child from paracetamol, and it can pass through breast milk so it's better to stop taking it and talk to your doctor. Or give your child formula if you need to take it to avoid it being transferred to them.