We just filed, FedEx arrived at the Dallas office 3/29.
We literally got the receipt letters in the mail Monday (4/22).
I'd say just keep checking.
I did not get an e-mail, but my spouse did (he is the green card candidate, I am the citizen). E-mail basically said, something happened with your application... went out and checked the mailbox, there were four letters, one addressed to me (I-130) and three addressed to him (I-485, I-765, I-131).