A lot of people seem to be responding to the idea of relatability/originality in a general sense and not your specific situation that you've noted, so I figured I'd reply to your thoughts on this directly.
First off, I think you are far underestimating the difficulty of doing strip gag comics. They are popular, sure, and it is "easy" to make them in-so-far-as they only need to be a one-off set of 3-4 panels, but they are not easy to execute well.
It's very hard to write them, write them well, have them land, have them make sense, and work for a lot of people. So, go easy on yourself. If some don't quite get there, don't beat yourself up over it. Just get started on the next and try to do better I think you're right that you're comparing yourself to others unfairly, and also not recognizing just how difficult this style of comic really is.
Easy to execute, very difficult to do well.
When I checked your comic, I could see why people responded this way. I don't know how you were taken aback being told it was an unoriginal idea- you redrew a meme.
That's the entire punchline of the strip, right, that you're referencing this meme?
I don't see any problem with that, except that you seem to be unhappy with this pointed out. This kind of joke, by design, is unoriginal, because it's referencing something the audience has already seen, in order to get a laugh.
Maybe the juxtaposition between a meme-referencing joke, and your wish to stand out and have your own voice and your own take is where this tension is coming from. Maybe you should give it a bit of thought- of what kind of comic you want to make?
I don't see anything wrong with making a comic that references memes or subcultures and is in-jokey. But maybe you're admiring comics that are "relatable" in a way that they create their own memes (like the "this is fine" dog), and that requires a different take than using already-existing imagery and icons. That's not to say you have to reinvent the wheel, but maybe put a little more thought into how you approach it? In this comic particularly, maybe instead of ending on a meme-inspired image, you could draw your own, personal reaction, or a way that your main character would respond that is unique to them.
Regardless, the response on Tapas seems to be overall positive- with people agreeing "same!" or totally getting what you were doing there. So I would argue that what you did IS relatable, by that definition. Things can be both relatable and unoriginal, and that doesn't make them bad and it isn't a dirty word. What matters is what you wish to achieve.