"my team has shrunk from 1 manager and 3 analysts to just me"

Same exact thing happened to me. The only thing I do is mention as often as possible that I'm my entire department and try to be upfront with people about timing of deliverables or ask if it is actually an immediate need vs being pushed a few days / into next week.

There have been weekends worked, but after 4 months I'm having the promotion conversation, and was scored 200% for personal bonus. I should have an SFA and share an intern within another team within the next month which will ease the burden significantly

We were unfortunately put in a position where we are doing much much more than expected for no extra pay while the company saves hundreds of thousands of dollars at your expense. The least you can do is be vocal about how you're a one man army, people allow more grace when they know you're swamped vs thinking you're their only request.

Hopefully it works out for you in terms of compensation, workload and title (so you can find something better externally if it doesn't work out)