Fumbling with words

Today I locked myself out of my car. My phone was also in the car so I couldn't use it to contact anyone. I ended up having to borrow a random person's phone because I didn't want anyone to hear me speaking to someone on the public phone. Anyways...

I'm waiting outside of a building and I see that this person is standing off to the side- so I decide to approach them. Of course, whenever I speak to someone my voice goes really high and I start talking really fast. When I asked this person for their phone, I came off as demanding and rude. I tried to explain my situation, but it sounded awkward and uninterpretable. Luckily, this person was kind enough to hand me their phone and let me call for someone to bring my spare key.

While I'm calling I say things like "I'm so sorry for this" and "thank you so much", but it was obvious that person didn't want to be around any longer. After a few minutes, I ended up having to text on their phone because no one was picking up. I handed the phone back to them and say "thank you so much for this". They ask, "are you going to be okay?". I say, "well, I texted so hopefully they see the message. If not, I'll-" at this point, my mind goes blank and I can't finish my measly sentence with "I'll figure something out". My fumbling of words felt like minutes rather than seconds, but in the end, he said, "...you'll figure something out?". Yeah, that. Then he left.

I feel so embarrassed. I really dislike being this socially inept. What's worse is that I realized that this person was in one of my classes, so I'll have to see them again. I really hope they don't remember me.