Is being clumsy/doing stupid things a symptom of ADHD?

TL;DR People have no respect for me because I keep doing embarrassing little things that I have no control over. Could this be because of ADHD?

I have a tendency to do really stupid embarrassing little things uncontrollably and people's constant negative reactions towards me in response are driving me insane.
I was riding with someone back home from college, and after making a stop I made my way back to the car and went to open the backseat car door but it was locked. The guy I was riding with gave me the key and I tried to fit the key in the lock but it wouldn't fit. I struggled with it for at least 20 to 30 seconds before the guy I was riding with told me to unlock the front car door instead and to just reach in and unlock the back car door from the inside. I felt extremely stupid because I had sat there trying to mess with the key and I didn't even think of that.

Another embarrassing moment happened on that same car ride where I went to pump gas and I kept trying to fit the gas nozzle into the car but it wouldn't fit. I kept struggling with it for at least 30 seconds before I realized that the green gas nozzle was for diesel. I picked up the black, nondiesal gas nozzle and it fit into the car perfectly. I felt like a complete dumbass again. I could tell the guy I was riding with was amused but he didn't openly mock me.

Without going into too much detail the guy I was riding with is in two of my Computer Science classes so I see him fairly regularly at school. From that car ride onward I can tell he has no respect for me and talks down to me condescendingly and I can guarantee it's because of these awkward stupid things that I keep doing. I seriously wonder if some kind of mental disorder is causing me to do this, and from what I've seen on the internet, Inattentive ADD seems to be the most likely.
Can anyone else confirm that these instances of stupidity are a symptom of ADHD? It's extremely frustrating when everyone around you constantly mocks you for stupidity that you have no control over.

I am extremely clumsy. I would love to know if this is part of ADHD.
Even if I'm at home by myself, I still have times when I almost trip over myself, or lose my balance.

When I'm around people (and this could be partly due to my AvPD) it makes me more tense, and thus more likely to act clumsily. Perhaps that is the same for you?

I do stupid things quite frequently. What I try to do now (I don't do it all the time) is to think, yes, to think making a couple of seconds stop before doing something.

Also, I started doing small things to keep myself on track of what I am doing. For example, I need to add 7 spoonfuls of coffee to the coffee maker, I count them repeating the number two or three times. Like this: 1, 1, 1, 2, 2, 2, 3, 3, 3.... slowly I don't get confused and end adding more ore less coffee to the coffee maker.

Also,double check, double check everything. Are your car keys in your pocket? Check before you close the door (especially if your doors close automatically).

Double check your turned off the stove, the iron... always double check... and do all these things slowly. Try to live your life in slow motion.

Yes