I filed my taxes by mail about 6 weeks ago but I still have not heard anything. I checked where's my refund and nothing. Should I mail in another copy?

Here is your answer

https://ttlc.intuit.com/replies/6013570

since you have already used the Where's my Refund tool, I would suggest contacting the Irs directly@Individuals:
800-829-1040

Customer service representatives are available Monday through Friday, 7 a.m. to 7 p.m. local time, unless otherwise noted. Residents of Alaska and Hawaii follow Pacific time. Puerto Rico phone lines are open 8 a.m. to 8 p.m. local time.

I hope this answers your question!