I stopped breast feeding 3 weeks ago my baby is 5 weeks now I wanna breastfeed again has my milk gone bad is it ok to let my baby nurse?

Go for it! There's no reason you shouldn't try to "relactate". Your milk is the best thing for the baby. You should get a breast pump, and pump both sides at the same time to stimulate your milk to come back. Also fenugreek tea can help. See a lactation consultant for more advice. Gook luck!