Why is the questioner experiencing financially burdensome circumstances and situations with his new car, even though he sacrificed a sheep for it when he bought it?

The calamities that befall you after purchasing the car are predestined. Therefore, cast away pessimism and know that this might be to avert a greater evil, or to raise your status, or to atone for sins, as stated in the Hadith: "No fatigue, nor disease, nor sorrow, nor sadness, nor hurt, nor distress befalls a Muslim, even if it were the prick of a thorn, but Allah expiates some of his sins thereby." And you must adhere to the prescribed remembrances (adhkar) that ward off envy. As for slaughtering an animal with the intention of gaining blessings or protection from the evil eye, there is no basis for it. However, it is permissible as a form of thanking Allah, and doing good deeds protects one from misfortunes and afflictions.