I got a new position recently as a deputy lead of a research group (this position is at a level comparable to assistant/associate professor in my country) at a famous institute. This means that the lead gives me tasks and I regularly report to him. In addition, the head of the department (to which my group belongs) is also giving me tasks, as I have been hired to help them both. However, this makes me overloaded and it is almost impossible to complete all the tasks assigned to me.
In addition to all this, I have to manage and work on 4+ projects (which are in their mid-lifetime) and write grant proposals, but so far there is no one in the group I am leading to help with this work.
I feel it is beyond my capability to manage all these things alone. Any advice?