I totally feel you on this! It seems like as soon as you've got one stage figured out and funds set aside for it, something else comes up and takes those funds right back out of your pocket. And it's definitely a full-time job in itself! When my kids were small, I felt like I was always running after them with my credit card in hand - especially as their tastes changed so quickly, especially with clothes.
It's exhausting and expensive! That phrase really is so true; it does take a village to raise a child - or at least, it would be nice to have that village of help! These days, I try to tell parents to make sure they keep aside some funds for themselves, as hard as it is, because it's just as important to keep yourself happy and healthy too - and that can also include some little treats here and there! Keep your own needs in mind, too, even if it's just a small indulgence every now and then. It'll help you feel human amidst the chaos!