clutch system question Options

[SAMIAM]

I was driving my car around for about 4 hours straight doing food delivery for a friends restaurant. car was running for a good 4 hours whether idling at the store or driving hard cause i was pissed off trying to find addresses. Anyways, the next day when i went to drive home, i got stuck in traffic and my clutch pedal started to feel like it wasnt retracting with much pressure and before long i found myself on the side of 495 and couldnt get out of neutral. after pumping the pedal for a while and multiple stops to repeat that i was able to limp it to a service station. i checked the fluid and it is dark like watered down coke. the mechanic on duty came out and bled the system and assured me that it was fine, i just had air in the system.

im not very automotive intelligent so please dont blast me for being dumb. About 2 years ago my mechanic friend helped me change the clutch master cylinder, and the part to the right of my exhaust manifold with the bleeder valve for the clutch system(cant think of the actual name for it). Also had a mechanic put an act stage 3 clutch about 5 years ago. Ive probly put 50k miles on the car since the clutch, and 10K miles since the master cylinder and that other part. After he bled the line, ive driven about 20 miles and it feels nice and stiff, and shifts perfectly.

so my questions are:

1-If my fluid is all dirty looking, it seems to me that somethings going bad?
2- Can aggresive driving/long idles cause air to get into the system?
3-Is there something i should check that a dummy like me could do?
4-Have you seen my baseball?