Help My admin area doesn’t work

Help me please as I’m panicking big time.

I have the Pandella theme and i was having problem that when I logged into couldn’t see my site so I couldn’t preview a post or anything. I submitted a support ticket to ask what to do about that.

They replied back to say try to deactivate some plugins as that could be the problem. I started doing that and I logged out to see if I would help me.

Now I can’t log back in. When i go to annanuttall.com/wp-admin and do my username and password It will come up blank. I tried refreshing nothing comes up and i even restarted my computer and nothing. I cannot get into my admin area.

How do I get back in? My Jetpack notification came up saying someone from China logged in:

A user with username “admin” who has administrator access signed in to your WordPress site.
User IP: 188.138.204.7
User hostname: 188-138-204-7.starnet.md
User location: Chişinău, Republic of Moldova

This is really bad, please how do I get this sorted and how do i back up all my posts? I sent another support ticket to the theme developer and waiting for a reply.

I tried it on another browser. I really need help. How do I fix this?

I really would appericate your help. Thank you.

Kind Regards
Anna Nuttall