I remember my first time on the freeway being a similar experience to yours, and a major psychological milestone.
Yes, you really have to watch those freeway off-ramps as many of them have a real tight bend, often sloping and with gravel at the sides.
I think your whole problem was due to, as you say, coming into the bend too hot (a very common mistake amongst new riders; and “fast guys”). Pay attention to the speed limit signs on the exit ramps as they often give you a clue as to how tight the off-ramp bend may be.
It’s never a good idea to take a bend with the clutch pulled-in. The best thing to do if you find you’ve gone into a bend too hot (which you can almost always prevent), is to lean more. So long as you don’t have a cruiser, the bike will lean a heck of a lot more than you’re usually willing to lean it. You lean the bike by counter-steering.
Another strategy to scrub-off some speed in a bend, is to sit the bike upright very briefly and apply both brakes, then ease-off the brakes and go back into the lean. You need to have mastered counter-steering and also have enough space to do this one. If not, you’ll run straight off the road. Try to brake OR lean as there’s often not enough traction to do both at the same time. When you take your MSF BRC, you’ll do lots of braking and swerving exercises, which should help some.
Make no mistake, going into bends too hot is one of the major killers of motorcyclists, so you’ve been warned.
Always do your braking BEFORE the bend, not in the bend.
Also, as you’re aware, it’s important to take a good line through the bend so as to straighten out the bend as much as possible and to let you see what’s ahead. The slower you go into the bend, the more time you’ll have to think about what line you should be taking based on the shape of the bend.
Anyway, you lived to tell the tale, now hopefully, a little wiser.
Oh! One last strategy… Avoid that freeway junction !
I’ve got a real bad one on my way home from work. Seven very busy lanes of traffic with cars merging off in the same few hundred feet of shared lanes that others are merging on in (criss-cross fashion). It’s the most convenient one for me to get off the freeway, but I just refuse to use it when it’s raining as it’s too busy and dangerous (I came off the bike there once before in the rain).