I think the mature thing to do would be to wait for the 2 week test to come back and not breastfeed your child in the meantime. Even if you know you haven't done meth, I would think the risk that you somehow have been exposed to meth should outweigh the desire to breastfeed.
The hospital is more concerned about the health of the baby than the desire of a new mother to validate their motherhood by breastfeeding. Seems okay to me.