brek pads
The e-brake cable(s) could be stuck.
If you are losing fluid and the pedal is low, you have a brake fluid leak.
Typically, that comes from having air in the lines.
Most likely has a leak somewhere in the line, or the switch in the parking brake petal is bad. my switch went bad, just removed the bulb, cheap fix
I do not, but depression could cause this.
Probable cause is a warped front disk brake rotor. The rotor can be "turned" to eliminate vibs if not too worn.
A hard brake pedal can be caused by several different factors. It can be as simple as the brake pedal getting caught on something to the power brake booster being bad. You could also have a brake pad or shoe that is sticking, causing the brake fluid to boil. When brake fluid boils, it expands and can cause the hard brake pedal that you feel. A brake pedal that is hard to press can also be caused by a build-up of water in the brake line. The water in the brake line lowers the boiling point of the brake fluid. A hard brake pedal can also be the result of a restriction in the brake line, such as a bent brake line or foreign material in the brake fluid. The most common cause of a hard brake pedal is the sticking brake pad or shoe, causing the brake fluid to boil. Tracking down what is causing the hard brake pedal can be frustrating, to say the least. Take the vehicle for a drive and when you come back, feel your brake lines near the wheels. Caution: The line may be very hot! If one is extremely hot, you may have just found the culprit causing the hard brake pedal.
It seems like there might be air in your brake system. You should try bleeding your brakes and filling it with fresh brake fluid.
Brake vibration is usually caused by the brake rotors being warped. The rotors must be machined or replaced to correct the problem. if you can feel it in the steering then the drums are or rear rotor could be warped
There are many things that can cause a person to feel nauseous. Pregnancy is one common cause. An upset stomach from something a person ate could make them feel that way. Motion sickness is another cause.
Gas is compressible, which means it can compress under pressure and cause the brake pedal to feel spongy and reduce the braking efficiency. Liquids like brake fluid are used in brake systems because they are incompressible, ensuring a consistent and reliable transfer of force from the brake pedal to the brakes.