Been having some problems recently with overheating and losing coolant and when I went to fill up the coolant I found this on the bottom of my radiator cap

Just need a second opinion if my car is done for.

The bit in question

 

looks like silicone, people love to overuse it because they lack the confidence to trust a gasket, or they replace gaskets altogether with it. you can tell what is siliconed in the coolant system by seeing this stuff squishing out of thermostat or water pump sealing surfaces. too much of it and it will affect coolant flow or block passages.

 

Does the car seem to be burning any coolant?
While running, with the cap off, are you seeing surging or bubbling?

If your coolant seals are intact from the tests above, I'd move onto checking the usuals: Thermostat opening, blocked cooling system, flushing, etc.

 

can also grab the fan and spin it with the engine cold, it should have some resistance and stop spinning as soon as you let go.

telltale signs of blown coolant seals are bubbling in the coolant reservoir and it overflowing/filling with coolant.

 

There’s some bubbles in the overflow and yes it has been eating coolant but the exhaust doesn’t smell like coolant

 

coolant doesn't always get into the engine, in a lot of cases it only gets overpressurized with pockets of compressed air and unburned fuel. theres this things called a "block tester" to help be more sure, harbor freight even sells them now.