Advice needed

Work is super stressful right now and we have a lot going on. I work with a team of 5 people and we all essentially have the same job duties except I work in a “specific” area while the remaining 4 work in another together. I’m currently doing the work of about 3 people with all the projects going on and I have asked for help several times but never receive it. I was told that another project is coming up and I still haven’t completed the one I’m working on now. Of course I’m frustrated. The building manager asked me if I am overwhelmed and I said “yes i very much am”. His response was “well that’s the cost of doing business”. Wtf… no offer of support at all. How do I handle this???