Exhaustingly anxious kid

Help! My daughter (7y) is anxious about everything. She goes in to every activity already stressed out and it could be something as mundane as just going outside or rain. I try to do calming exercises with her to ground her like her hearing thunder and now wanting to close her bedroom windows because rain is coming and she’s all frazzled. I asked her to take a deep breath, asked if she is in danger (no), assured her she is safe, looked outside and confirmed there is no rain so she doesn’t have to close the window, and even if rain got in, I asked her what is her concern and she said everything will get wet. I assured her the windowsill will get wet and yeah that can be annoying but we’ll wipe it away or it’ll dry on its own.

I try to be empathetic and patient but after the 10th panic of the day, that’s out the window. I’m basically a married single mom with an overflowing plate of responsibilities and I don’t know how to better help her because I’m at my wits end.