Kristy, I not really sure if I can give you the right answer. I do know that hcg is a natural female hormone. It can do different things to different women. It is possible that it is causing you to have bleeding, overriding the IUD. I do not know much about them, other than as a contrceptive.
If you do bleed, stop the hcg while the blood is bright red, usually for a few days. Then resume the injections when the color becomes darker. Make note of your bleeding cycle.
I have not had TOM for four years. However, being on the hcg has slowed down the hot flashes I get and on occasion, there is just a wee bit of pink from "there".
Yes this is a pregnacy hormone, but, if you did a pregnancy test, it will show positive, even though you are not.
I do not know if it will go away. You may be that way while you are on the hcg. After that, it takes a few weeks to "normal" out again.
Sorry for the unpleasant monthly side effects.