Hi Allana1133
Any change in MHT should be discussed with your doctor. Your doctor may suggest you try a lower dose of estrogen to see if that reduces the side effects and allows you to continue the progesterone. Once you stabilize on a lower dose, you may find it's not as difficult to increase. There are some women on this forum that take very low doses of estrogen and benefit from them.
It's not going to do any harm in the short term to continue with the progesterone, but you may not feel as well on it as time goes on. The symptoms of hormonal imbalance will eventually become apparent.
Assuming no other causes, spotting will be a sign of too much progesterone. Your doctor can help you find the right balance for you. There's usually some experimentation involved. At least you've learned that you get along with progesterone.