Uncontrollabe MASSIVE PUMP in thigh suddenly

So today was leg day, and as always, i was in warmup..doing free squats, 25 reps , 2 sets done.

I walked towards the position, no pain, got into front squat postion , no pain, i go down and there's a MASSIVE painful pump suddenly, it got so bad my friend had to walk me so i can sit.

It isnt injury, i'm affirmative on that , the pain is exactly like the pump you get after doing your highest rep with highest weight squats.
Except, this doesnt subside over time if im doing sitting motion. Once the motion is complete, i can barely feel it, but again while standing, it hurts.

I was able to do everything other than squats, or anything involving the squat motion.
After 10 hours or so, the pump or pain has subsided by like 30%.

Anyone has a guess what happened ? THe only different thing i did today was i started 5mg creatine and a cheap whey powder. Diet , clen same.

Notes: No join pain, no medical history of any problem ever.
THe pain is only in front side of thigh.
It occurs only DURING the motion, not before it or after it.

I still have a low back issue these days from my training in my 20s...
Anyway what kind of pain are we talking here, low back, the sciatic nerve pump?
You're fucked if its that pumping in the low back where you cant move properly (i still get this shit if im doing too much on legs/back)

Also, go to a doc and get an MRI asap.. i didn't see an update here so at a minimum go get checked out

Clen is the culprit