Don't stress too much about it. There are plenty of people like you who haven't heard anything from USCIS (Including me). The only thing you can do is be patient and wait for a response. And, when you calculate the time for your application, you shouldn't include holidays and weekends because most offices are closed on those days. To get an accurate working days, you can visit http://www.workingdays.us/ and enter the date when your application was received.
Welcome to the forum and Feel free to ask any questions. They are plenty of people willing to answer your questions.
G'Luck with everything.