New job anxiety

I’m 32 and I have had a total of 4 jobs since I started working at 18. One of my jobs I’ve had for the majority of my time working 12 years. Half of the time I had this job it wasn’t very great with money or hours but in the second half during Covid it became my main source of income because it paid me alright and I was able to be more full time. This job has always been a stressor of mine but my location closed down in February and it got worse. I got added more responsibilities with no extra pay, it was busier, and I’ve lost respect for the company and my boss. I’ve been job searching on and off these past two years and finally got an offer that I accepted. It’s a pay cut because I have to start over but I have more opportunities than if I stayed as I have reached as far as I could go in my current position. I have terrible anxiety that I’m making a huge mistake and it has been looming over me since I accepted the offer Monday. I have good support from my family and my boyfriend that tell me it will be worth it but it will take time to get used to the change. I won’t know until I work there. How can I manage my deep anxiety as it is so strong? I take medication for it now that I’ve utilized more since I’m not normally this anxious. It’s so bad that my anxiety is intrusive in my sleep. I’ve also been depressed too because even though the job got worse in the end it still supported me the years I have been there.