Merciless Crushing Defeat

So tonight at class was pretty frustrating. Since my last client of the day was right across the street from my gym I was there early and stretched out and warmed up a bit. When the striking class started they were doing all kicking, so I decided to join in. I have a long TKD background and I like kicking. So we did about an hour solid of kicks. I was good and warmed up when the grappling class started. I'm kind of half in the intermediate grappling class, I'm attending both the intermediate and the basic class because I like the grappling and need all of the help I can get. So needless to say most of the people in this class are more experienced than I am. And all of them are quite a bit bigger.
So we're starting out the month with a day of light grappling since several of the guys have amateur fights coming up and have MMA class after the grappling class. The first guy I roll with is monstrously huge, about 220 lbs. He's new to Hardcore, but has had some experience somewhere else. I'm not sure what it was. I held him in my guard for a while, but every time I tried to do anything he just out powered me. We did this for a while until I got bored and started trying crazy shit just to hit something. He ended up catching me in a guillotine. Repeat until he catches me with an RNC. So he decides to go get some water and I wander around the mats and watch some of the other guys for a bit, then I get to roll with one of the more experienced guys. He's about 180 and FAR more experienced than I am. So I spent about 15 minutes just getting submitted in ridiculous ways trying to find a way to pass his guard. I was not successful. So, quick water break for me then I roll with one of the guys closer to my experience level and size. He's about 165 and has been going to the intermediate class about the same amount of time I have. We were very back and forth positionally, both trying out some sweeps and things. But the strength difference really told. He was able to fight out of my RNC, and pull out of my armbars. I couldn't do the same with him.
So all in all it was kind of a frustrating night of getting my ass kicked. I know I'll get better with time and be able to handle the weight disadvantage, and in fact with the bigger guys in the beginners class I do just fine. But the combination of weight AND experience advantage makes for a disheartening time.
I did internalize one thing though, EVERY time my hand hit the mat the second guy I rolled with jumped on it and rode it to Kimura town. I now have that reflex pretty firmly ingrained.

Opponents hand on the mat = Kimura town.