Application was received on April 15th but still nothing in the mail

When I check my receipt number on USCIS website it says that my forms I-765 and i-131 were received on April 15th and receipt notice was sent to me but I still don't have any mail from them. According to the same page i-485 was received on May 11 but nothing yet in the mail also. Should I be worried by now or is this considered normal?