Messages Coming from Email on Macbook - can't add phone #

Hi. I recently tried to save space on my Macbook by optimising my storage and storing my messages in the cloud but ever since I did that, I have been unable to receive text messages on my computer. I can send them, but they send from my apple ID not from my phone number. Under the message settings, the option for where I can be reached for messages at only lists my email address and is grayed out. I've tried signing out and disabling messages in icloud and the option for "start new conversations from" is also grayed out. I've also updated and restarted my computer. Please help!