We understand that you're going through a challenging time, experiencing unusual behaviors and thoughts, and you're seeking God's help. Firstly, we want to assure you that the power of Jesus Christ is the only way to be saved and there is no other name that we can call upon to be saved. Abstaining from food is not called "abstinence". Abstinence is avoiding sinful behaviors such as sex before marriage. What you are referring to is called "fasting".
Fasting is a biblical practice that can bring us closer to God, but it should be done with the right motives and in a manner that aligns with Scripture, which gives us some guidelines for fasting. We should fast in secret. We should not boast about fasting and we should not get into legalistic debates about its duration.
So let us first address that fasting is not commanded by God and there is no right or wrong duration. We are told to not fast as the hypocrites do in Matthew 6:16 WEB:
Moreover when you fast, do not be like the hypocrites, with sad faces. For they disfigure their faces, that they may be seen by men to be fasting. Most certainly I tell you, they have received their reward.
But if you claim to be a Christian and are truly born again, then you have the Holy Spirit that dwells within you. Demonic attacks will always try to defeat the Holy Spirit's work in your life.
1 John 4:4 WEB:
You are of God, little children, and have overcome them; because greater is he who is in you than he who is in the world.
We should be careful to not give an undue attention to demonic attacks. Instead we should focus on God and His power.
1 Peter 5:8 WEB:
Be sober and self-controlled. Be watchful. Your adversary the devil, walks around like a roaring lion, seeking whom he may devour.
The Bible tells us that the battle is in the mind, and that we should take every thought captive to the obedience of Christ.
2 Corinthians 10:5 WEB:
bringing every thought into captivity to the obedience of Christ;
Let's pray together for you:
Dear Heavenly Father,
We come before You in the name of Jesus Christ, lifting up our brother/sister in their time of need. Lord, we ask for Your divine protection over their mind, body, and spirit. We rebuke any demonic attacks or strange behaviors that may be trying to influence them. Lord, if they are fasting, we pray that You would bless their fast and reveal Your will to them during this time. Help them to focus on You and Your power, rather than the enemy. Give them strength and endurance as they seek Your face. We declare no weapon formed against them shall prosper. In Jesus' name, we pray. Amen.
If you continue to experience strange behaviors and thoughts, we strongly encourage you to seek help from a pastor, counselor, or trusted Christian friend. It's important to remember that God has given us a sound mind, and that He wants us to live in freedom, not fear.
2 Timothy 1:7 WEB:
For God did not give us a spirit of fear, but of power, love, and self-control.
We are here for you, and we are praying for your peace and protection.
Prayer Focus: God, Thank You. Thank You for loving me. God, I ask You in Jesus’ name bless me with everything that I stand in need of and everything You want me to have. Bless me to know You in truth, fall in love with You with all my heart, mind, soul, body, and strength and never fall out of love with You. Bless me to have an ever growing closer stronger, more intimate relationship with You. Bless me with the love, desire, strength, and the spirit of obedience to always delight myself in You, seek first Your kingdom, and Your righteousness. Help and strengthen me God to always respect and obey You. Bless me to trust You with all my heart, acknowledge You in all my ways, and lean not to my own understanding. 
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