Some have tried to argue that anyone who is oppressed by Satan, or one of his minions, must be possessed by said demon. Well I don't find any support of that in scripture considering there were many, Job for example, who were very oppressed but were not possessed in any way.
I want to focus on the oppression for a few moments only because I feel that there are more people out there suffering with this than anything else. To be oppressed means to be treated unjustly or with cruelty. To be under a state of mental distress to feel as if you are bring forced into something without any means of escape.
There are many people in this world today who feel this way. To say that everyone is oppressed of Satan may be overstated, but I do feel that there are more out there than we care to admit. So what can you do?
First of all don't feel guilty! These emotions of depression and exasperation are real, but do they stem from reality? In other words are we afraid of nothing? When you feel guilty for feeling guilt you will get stuck in an emotional feedback loop, that if you don't do anything about will take a lot of work to get out of.
Secondly, where you are being attacked is probably an area where you are weak. If you are afraid of people or of money. Then these areas can change your mood and enslave you in it's bonds of oppression. Admit your weaknesses and give them to God. He isn't going to be upset with you for doing it, He already knows and wants you to give your fears to Him.
Thirdly, Who is feeding the monster? Usually there is someone or something that is "poking the bear" as it were. Now before you go divorcing your spouse or quitting your job let me be clear here. That person may not know what they are doing to you. You need to determine whether or not they intend any malice against you. Here is a rule of thumb that is always true. Your messed up and so is everyone else, so don't' be surprised when messed up people mess up.
Fourthly, don't underestimate Satan and those who work for him. You need to pray and do some spiritual warfare. Now before you start looking for demons under the couch or looking suspiciously at the neighbor here is what you need to to. Ignore the enemy, don't listen to him, don't believe a word he says. Even if the enemy tells the truth it is only to his advantage, never yours. Focus on the one who has won! Jesus! Take authority in His name and tell the Devil what to do and ask Jesus to defend you! Remember the Lord's prayer, "keep me from temptation and deliver me from evil!" In other words, "Jesus, get me as far away from Satan and his plans for me as possible!"