Oh you poor thing! You must be at your wits end! I did a google and found a few approaches.

" One approach that we used was to explain to the child that our teeth are for chewing food...not biting people. As long as everyone was consistant it really work a lot. We had a child that would bite when she got frustrated, tired, hungry, and even excited. For this child the method above did not work so we had an object that she could bite. We gave her a teether or another soft object and told her that if she felt she needed to bite something she could bite that. We showed her where we kept it and she would go get it if she needed it. It worked very well and eventually she stopped biting even that."

Maybe a sit-down with your childcare may help if you or they feel it isn't getting better. Hugs to you I would imagine it too be very stressful to get negative feedback about your little one.