Wish I could help you to feel better and somehow help you not panic. I'm sorry for how you must be feeling.
That clot is small in size. When I went to a&e (the er) a week and a bit ago, they asked me if I'd had any clots with my spotting. I said I didn't think so? And the nurse said don't worry, it's just a question, it's not for sure that it means anything bad if you have.