Breastfeeding

Hi mummies, i need help. I stopped bf when my LO is abt 2 months. Mainly because of my constant cracked nipples everytime baby bf. I have been giving her formula milk ever since. I can't stop feeling guilty of not bf baby. She's 4 months + now. And i want to bf her so badly, even if it's exclusive since i am a full time working single mum. I am so afraid that i no longer sustain any milk in my body for her. Is there any way i could reproduce the milk or if those lactation booster helps? 🥺