[MI] Received my first HR complaint, feel awful

To preface, I’m a 26m that works for a nonprofit association.

Last Friday at an even hosted by our association at an external vendor, I met a woman from one of our member organizations. This was the first time I had ever met her and we do not work together, neither in a physical nor in a collaborative sense. After chatting and exchanging contact information (in an admittedly professional manner), we went our separate ways. Later that night, I texted her something along the lines of “Hey this is __ from __, I know this might be unprofessional but I thought you were cute haha what’s up” and left it at that. Part of me regretted doing so, and I’ve also never done something like that before with anyone I’ve either worked with or met in a professional setting. I received no response and figured that was the end of it, no big deal. But today, one week later, my supervisor and HR representative called me in and notified me that they’d received a complaint from our member organization’s HR department regarding the incident. Granted, neither of them seemed too upset, and my supervisor stated they didn’t really think this was that bad and categorized it as a “learning experience.” Regardless, I feel awful and am super embarassed. I would never want to cross that line and make anyone uncomfortable in the workplace, and I’m also not the kind of person that would escalate a situation after someone simply didn’t reciprocate interest. In situations like this I always err on the side of professionalism, I’m not sure why I didn’t in this one (I guess I thought that since we didn’t work for the same organization nor collaboratively across organizations that it wouldn’t be an HR issue). Again, I just feel bad for making her uncomfortable and embarassed that my supervisors had to deal with this/now might think of me in an unbecoming way. Don’t really have anything to ask, so I apologize for that aspect. Just feeling shitty and embarassed.