Going back to work and facing a colleague and feeling anxious

I am having some anxiety about going back to work in the fall and start working with an overly competitive and jealous colleague who was prying on my private life when we worked together in the past. I tried to set boundaries with her, but it made things awkward. Now, when I think about going back to work along with the Covid 19 situation, I just feel like scared and fearful. How can I change my thoughts and actually look forward to work?