You are using the wrong disc, based on your links.

The discs you've linked are for stainless, not mild steel.

Basically the different types of disc use a different binder (glue) which holds the abrasive particles together. The idea is for the disc to wear down just slightly faster than it builds up metal particles, so it doesn't clog.

You might recover the disc if you did a heavy (push hard) series of cuts on a couple of bits of scrap metal. It'll clog again though.

Continuing to use it as-is is dangerous as the heat generated by the rubbing action of the clogged disc will eventually cause the binder to break down and chunks of the edge of the disc will be ejected at high speed.

Whatever you decide to do, in terms of trying to recover the disc you have, you must have the guard in place (and correctly positioned) because there's a non-zero risk of bits of the disc coming off.

There's a reasonable argument that can be made for binning that disc (because it'll only clog again) and buying the right type for the metal you're cutting.