Did you mail the Form 1040X amended return? It cannot be e-filed. You have to print it, sign it, and file it by mail. If you didn't mail it, you didn't file it.
The normal processing time for an amended return is up to 16 weeks from when the IRS receives it. Starting about 3 weeks after you mailed it you can check the status by using the "Where's My Amended Return?" tool at the following link on the IRS web site.