In my humble opinion, limited fabric purchases that help to bring some joy (back) into your life are totally justifiable. I think a lot of us find ourselves in this thread because the fabric is becoming burdensome. So many reasons for this - could be lack of time, inspiration, or storage space. But whether it was gifted fabric or pink or just a moment of much-needed mental health retail therapy, that spark of joy makes it a good decision. No matter what kind of "diet" you're on, allowing yourself to satisfy a craving with a small indulgence is generally better than causing yourself increased pain and anxiety by depriving yourself.
And remember, we are all travelling this path together and we will be here to listen and commiserate, to encourage and support and to give you a helping hand back up onto the wagon no matter where you find yourself on the journey. :-)