Mazal tov on the birth of your baby!
It is very common for women to have irregular bleeding in the first year post-partum, especially when nursing. This varies from woman to woman and, for each woman, from pregnancy to pregnancy. It is possible that you will now be menstruating monthly, but there is no way to know for sure.
You do not indicate which IUD you had removed. If it was copper alone, that is unlikely to affect ovulation. If it was a progesterone-secreting IUD, there may be effects.
For future reference, in case you wind up with staining, we recommend reading our site’s articles “Stains” and “Toilet Paper“.
Please write back with any further questions.