I need some troubleshooting help please

I've had the gaggia classic pro for about 8 months now. A lot of times, I forget to take the grounds off.

And I guess I did that so many times that it finally clogged the shower screen last month? The problem then was instead of water pulling through the grounds, it started blasting water through the side of the portafilter.

It didn't really make sense, but I just took off the shower screen to scrub it down to see it it solves it.

It did.

Then for 3 weeks, it worked fine.

But it started happening again, so this time, I did the same thing. But instead of pulling correctly now... the flow is reduced to just dripping! I have to wait like 5 minutes just to pull 1 shot of espresso.

When I take off the portafilter and just turn on the water, water seems to be coming out of the screen fine, so I'm a little confused what to do next.

Any advice?

Thanks