Hey goddess, It sounds like you have alot of responsibilities and are very frustrated
. I feel for you greatly as I used to have a job just as you have described...too many things too do to and no help or support from my supervisor who just kept piling stuff on top of me. I managed 2 psychiatric care facilities for 11 years...it was tough and in the end I got burnt out and did end up leaving.
In my opinion here I dont think the main issues are with you so much but with your supervisors and lack of communication and support your getting from them. For those of us who do take ownership in our jobs and try to complete tasks as expected it is or can be emotionally difficult to handle when we are unable to finish something. I am the exact same way. We take pride in what we do and want to know we are doing a good job, not falling behind, are able to keep up with what is expected of us. This is what makes us comfortable in our work and even content to stay at one job position for longer periods of time.
As for the supervisor that responds to you with "What?" when you say something, maybe think of a nice way to address this with them. This is not an appropriate way to speak to anyone as I am sure you know...and can tell it bothers you greatly. It would me too. Maybe they have so much on their mind they dont realize they are responding in this manner but it is still rude and if you bring it up I dont see that there would be any reprucutions from it.
Then I would make a list of all of the duties that you do on a daily and weekly basis then ask for a meeting with the supervisors. If they are aware there is a shortage of help already then you can give them your list and address your concerns of having not enough time to complete your regular duties because you have to cover reception and are interrupted all the time. If they dont respond in kind to this then I would say it may be time to look for another job. It would surely show you that they have no care or concern for their employees or the amount of responsibilities they have.
Stay strong dear