I've been working at my company for 6 months now, in a niche field in the healthcare sector. While I'm still at a relatively junior level, moving jobs gave me a hefty salary increase and the job offers a wide range of benefits. When I first started, I was placed on an innovative project where I was working with multiple stakeholders and clients, and had ownership of a major deliverable. Two weeks in, my manager asked if I was willing to help develop a simple deliverable that would be strictly for one client's use, and would take no longer than a month. This project was in a field unfamiliar to me but I agreed without asking any further questions as I was eager to please my manager.
The initially 'simple' deliverable has become a much more complex tool, and has prevented me from working on any other projects, including the innovative one mentioned above. It has been six months now and there's no end in sight, as the client has been requesting increasingly complex updates that I'm struggling to complete, as my knowledge of VBA is limited (I have learnt a great deal since starting so that has been the one positive).
The client is also very difficult, and in most of our calls she insults my work or talks down to me. As a non-confrontational person, this makes me feel really anxious whenever I have to communicate with her and at times I feel like not going into work or checking my email inbox as I'm scared that I'll have an angry email from her. My manager is present in most of our calls but I'm mostly left to present and talk to the client. He does also check in with me every week, but at the moment I'm feeling like I've been left alone to do everything. The client and project has become a bit of a running joke in my company, which I no longer find funny as I'm the one who has to bear the brunt of it all.
I'm disappointed that this is all I've worked on since I started this job, and apart from the VBA experience I've gained it's not something I could put on my CV as it's in a completely different field to what I'm supposed to work in. I've told my manager before that I'd like to work on other projects and while he did place me on something more suited, the amount of work I had to complete on the first project prevented me from being able to make any meaningful contributions, and at present I'm no longer on that project.
I'm now feeling completely overwhelmed with the amount and complexity of work I'm expected to complete. This project has negatively impacted my mental health to the point that I'm crying about my job at least once a week. It's also starting to slowly impact my work performance, and at times I'm struggling to find any motivation. The thought that I could be working on this project for another 6+ months terrifies me, and I've starting to think this will negatively impact my career development.
I'm thinking to speak to my manager again about all of this, but would like to frame it in a way that isn't confrontational. I'm quite an emotional person so I'm afraid of breaking down and messing up the meeting. Any advice on what to say (or if I should say anything) would be appreciated.
TL;DR: assigned to work alone on an increasingly complex project with a difficult client, it’s negatively affecting my mental health and performance and is stopping me from working on projects more aligned to my experience/field. Not sure what I should say to my boss.