Brake Light on Dashboard lightly on?

Hi there thank you for your patience,

Just today, I started the car and released the breaks and realized the brake light on dashboard was still dimly on. Never happened before, and my car is slower than usual. It felt like I was driving the car while the breaks were somewhat still on.

While parked, I repeatedly appiled and released the emergency brakes but it doesn't help.

Please tell me what to do and why does the brake light on dashboard becomes dimmed but not off, then fully on, then dimmed again.