Unfortunately, in an "at will" employment relationship, an employer can hire or fire in its sole discretion as it sees fit; for any reason or no reason at all; with or without notice. So your termination appears to be lawful.  That is unless any of the following applies: there is a union agreement/employment contract that doesn't allow for the circumstances of your discharge; your dismissal violates existing company policy; or your termination stemmed from some form of actionable discrimination. Absent any of the foregoing, your former employer's actions were perfectly permissible.