Join Date:Joined: Jul 2013
You didn't give many details, only a summary of ostensibly erratic application behaviour. It's nigh impossible to reach any conclusion in the absence of abundant details. So for peace of mind, I'd suggest resetting everything and start over.
So back up any files, photos, etc that you wish to keep. Then use the Odin program to write a 100% stock firmware to your phone. Followed by a factory data reset. That should remove any spyware, malware, malicious apps or anything else short of physical modifications to your phone - which is an unlikely scenario.
As to a cloned number.. that seems unlikely. But if you believe so, then have your provider change your number, get a new SIM card, etc. Or better yet, simply change providers.
Then you will have a stable base to proceed from.