Contraceptive injection

I’ve been on the injection for over a year and ever since my first shot I’ve had my periods once every three months and when I do have them, they’re light and doesn’t last long. I’m not due another dose until towards the end of January, but it’s come early and it’s lasted for over two weeks which isn’t unusual for me. I bleed on to my pad, but whenever I go for a wee the amount of blood that comes out is a little worrying, I’m also having small clots on the tissue when I’ve wiped.

I know periods can be irregular on the injection but it does still seem unusual and it’s worrying me. I can’t get to the doctors due to it being Christmas so just looking for some friendly advice please