What are the signs of carbon monoxide poisoning? I have frequent headaches and tire easily sometimes. Can my car leak carbon monoxide fumes inside?

Yes, risk is present. You may experience headaches only while in your car, your fingertips may turn cherry red, you might be spacey, light-headed, dizzy, nauseated, and if so, could be carbon monoxide exposure. So, if you have an older car, and visible exhaust with a lot of wear and tear, best to have it checked. Also, at home, always have place carbon monoxide detector, as furnaces have potential for harm.
Headache etc. Symptoms of mild acute poisoning include lightheadedness, confusion, headaches, vertigo, and flu-like effects; larger exposures can lead to significant toxicity of the central nervous system and heart, and even death. Following acute poisoning, long-term sequelae often occur.