Every day I check my

Question

Every day I check my Mail at Inbox. To day I open and Check. Then I try to "delete" unwanted two mail by marking it green tick on the left hand side of the square box. I very sure that I don't marking all of them. But unfortunately all of mails are deleted which is very important to me. So I request please help me how do I get back my important mail file which is send to me.