New Primary Domain and Now I Can’t Login

Hello, I just changed my primary domain and now my user/pass isn’t working. I tried re-setting my password and I know i’m using the appropriate username and I still can’t login. also, half the time when I type in wp-admin at the end of my website name it just directs me to my homepage, not a login page or the dashboard. No idea what’s going on…if anyone can help, please advise!