[kwiromeo]

I agree with this. Definitely learn to push back. I've been in a similar situation albeit in aviation systems engineering. The way I dealt with a lot of incoming request was to always point out that I had things that were already on the back burner. I would phrase it along the lines of: "I am currently doing Y, and was planning to do X and Z next. Is A you're asking me to do urgent? If yes, I can do it after Y of you're okay with X and Z being delayed." This usually got me a response that indicated want the priority was. I would also really try not to let the current work I was doing being stopped. Stopping something midtask would always make the same item I was working on take longer, so I would push back if they tried to stop current work midstream. I would say: "I'm X hours away from accomplish this task. Can item A your asking wait until then?" That usually got me some good relief.

One item to note that this is also an opportunity to request some training, either formal or informal. Find the skill that if improved would easily increase your task output, find formal training for it in the area or nearby. If you can put a cost benefit analysis on a 1 page word doc, you might be able to take this opportunity to improve your skills as well.