Hi Julissa,
I understand the importance of getting Office working again. The problem usually occurs because the license links to your Microsoft account, not the product key.
First, go to account.microsoft.com/services and sign in with the account you used to activate Office. Check if Office Home & Student shows up under Services & Subscriptions. If it does, click Install. If you don't see it, try a different browser or clear your cache.
If the license isn't listed, it might be under a different email. Do you remember using another account? Also, did you remove all old Office versions before reinstalling? This can block the process.
After you sign in, tell me what you see so we can move forward.