I feel like my life has stopped, what should I do?

I was sick for 17 days, I had very bad food poisoning. I wasnt able to move physically,I couldnt eat, sleep or work on a personal project. So I took time off from everything. But the lockdown, depression and anxiety made each day even harder because I wasnt able to do anything.

I was depressed before the sicknessad already feeling down the sickness made it even worse

During the two weeks, I accepted a two weeks job offer since the payment is very good and I will work on something I love so why not? I will be okay after two weeks... but thats what I thought.

Today was the first day I work on the project and I feel so burned out. I work very slowly, I cant focus, I cant stand working, my depression and anxiety are still making everything hard and I dont know what to do, I feel weak even tho I recovered, all I know that I cant work and I feel very tired and I dont know why. I feel so low.

I only worked for one day and I think about quitting because if I kept that way I will not deliver good quality. But the problem is that they really need me because no one is available for this work and if I say no after they waited for me Im afraid they will never ask me for anything again. I was very excited last week and I saw the project but I didnt know I will not be able to work like that how could I know.

I feel like all I wanna do is sleep, I feel like my life has stopped and I just cant move any more

I feel very lost right now and I dont know what to do. Any advice?