caught between two stools

To be caught or stuck between two things and thus unable to adequately do or accommodate both. Primarily heard in UK. I was excited to start taking night classes after work, but now, without enough time to devote either to school or to my job, I feel like I'm caught between two stools. Come on, this project needs your full attention right now in order to be successful. I don't want you caught between two stools trying to help the benefits team and our team. I know some people excel as utility players, but I really need to play the same position every day. For me, it's mentally exhausting to be caught between two stools.