My work friends turned on me, advice?

I work in healthcare and I just finished school in March so I haven’t been working that long and I’m still learning the ropes. At first, my coworkers were really friendly, I work with mostly women, and we got along really. Then one of the older employees came back, he’s around my age and they all pretty much told me that they all find him attractive. I’m a girls girl so I would never intentionally step on anyone’s toes but I was friendly with him since it was our first time meeting. Long story short, he flirted with me a bit last Wednesday but I turned him down because I don’t date people I work with plus I didn’t want to make things weird with the others. Today, when I came in they all were calling him my boyfriend and were making weird jokes and being lowkey catty. They basically left me on my own and wouldn’t help if I had a question. Anyway, before we left today I tried to be the last one to leave to avoid him but I had to let my dog out so I ended crossing paths with him when leaving and he directly asked me out. I turned him down again for the reason I mentioned but I know tomorrow will be extremely uncomfortable since that’ll get spread around fast. I normally don’t care what anyone thinks and I try my best to avoid drama but I’ve also never worked in an environment like this. Not sure what to do
My work friends turned on me, advice?
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