What KayXo said. If you think you have a clot, or if you think you might have a clot, call or go to a doctor, and if at all possible rest and minimize movement until you sort things out. If it IS one, you don't want to dislodge it. (Incidentally, get in touch with a doctor even if you are not being medically supervised. It's ok if they are not treating you regularly.)
Also, forget about worrying about whether you can continue HRT until you sort this out. A clot can be permanently debilitating or even lethal. There are alternatives for HRT that are less likely to induce clotting and these can be explored later if necessary.
That said, from what I've read, this does not sound like one. But don't trust the Internet on this.