I put a lot of pressure on myself to do things right. I sometimes think of rules that sound plausible, and because they sound plausible I follow them. As an example the “Bible says to be responsible with money, so you can’t buy anything that’s unnecessary.” This causes a lot of anxiety and makes daily life difficult. It can get extreme such as, you have to live in your current town forever because you didn’t forgive a stranger who was annoying and apologized about it.” These thoughts sound so convincing and it scares me. I once stopped showering, and wouldn’t eat or drink for hours. I know that’s crazy and disgusting but I did it because my thoughts had me convinced to do these things.
I have a lot of questions, but I don’t want to overwhelm anyone.
"Every word of God is tested; He is a shield to those who take refuge in Him. Do not add to His words or He will reprove you, and you will be proved a liar" (Proverbs 30:5-6).
Since every word in the Bible is tested and proven to be true, the prophet Agur concludes that you cannot improve upon perfection. You can't add to the truth and still have the truth. The Bible also states that it contains everything needed for life and godliness (II Peter 1:2-4). Yet, you decided to add rules to your life that are not found in the Bible. These made-up rules are impossible to keep and so you use your failures to berate yourself.
Solomon warned against this line of thinking. "Do not be excessively righteous and do not be overly wise. Why should you ruin yourself?" (Ecclesiastes 7:16). Trying to be more righteous than God said to be only leads to personal ruin.
Your problem sounds like a few other people I know who have a mild form of schizophrenia. If that is the case, there are very effective medications that reduce the symptoms to a manageable level. My best advice is to see a good psychiatrist and see if medication can help you think clearer.