Hi lifejoy -- sorry you're struggling! So, I'm going to project and hypothesize a bit, and if I'm completely off-base, forgive me. You sound bored. You sound like you love your baby (now toddler) more than life itself and truly enjoy your time with her and yet periodically find yourself bored shitless at the monotony of day after day with an always-needy small one and feel incredibly guilty that you are bored and so work out that emotion by buying stuff, because it gives you an endorphin hit and is either rationalizable (it's for the baby!) or makes you feel like you're still worth something for a moment (shinypretty for you).
I could be completely wrong. Maybe that was just me. If so, forget the previous paragraph. ;-)
In any event, I suggest a thought exercise: what if you viewed yourself not as a SAHM, but as already FIRE'd? Because, umm, you are! You never have to work again if you don't want to! So: what do you want your life to be like when you're FIRE'd? What is that mental vision that you have been working and saving for? Not the debt you've been (appropriately!) running away from -- what have you been running towards? IOW, stop viewing FIRE as some amorphous future that you have been planning for, and start realizing that it is your life, right now, this very day. So is this the life that you want -- who you want to be and how you want things to be for the rest of your life?
To me, this sounds like someone who either doesn't have a clear vision of FIRE (beyond "not have to work") or who had a clear vision ("stay home with my baby!") and yet is finding out that is not as all-encompassingly fulfilling as she expected it to be. The spending is just the symptom, the temporary band-aid to plaster over the hole in your soul. Which means it's time to re-think -- to either develop a clear vision and plan, or to revise the plan to add in something else that you need. Now, for many people, the advice is to go back to work; certainly I was very happy to go back to work and exercise another part of my brain that did not get worked when I was home with my toddler. But you're FIRE'd! You don't ever have to work again!! So what do you love, besides your child?? What part of your brain or heart or soul feels missing, lacking, wanting? Your creativity? An intellectual challenge? Just throwing yourself whole-heartedly into something and forgetting everything else? Adult time with friends without your own personal remora demanding your attention? Commitment to a cause you care about? Physical challenges? There are as many different flavors as there are people. Figure out what yours is, and then work that into your life.
In the interim: get enough sleep. Eat well. Give yourself downtime every day. Get physical activity. And try something new/different/hard, just to remind youself that you can, that you're still a powerful woman. Because you are.