For past 4-5 months I've been engaged in an independent project in my company. What I'm building is going to be used internally. 4 months ago, a senior architect (now a non-technical upper manager) started mentoring me unofficially, and soon I started directly reporting to him.

I'm working independently on a tool for internal use by the field engineers and support engineers. However as I'm the only person working on this, there are several cons:

• The person I report to is the only one who suggests the solutions
• The scope is not fixed - and changes as per my progress and the whims of this guy
• Sometimes I feel kinda alone

I'll be taking a long break after two months - and have to finish this project by then. However for the past few days I feel I've been a little turned off by the idea of working on this project. Although there are people from other teams who might take me in temporarily (we've discussed this already), but my manager wants me to stick to this.

How can I convince this manager (with 20+ years experience) that I should take a break and maybe work with some other projects for a few days, and then resume working on this? Would it be a negative sign that I can't continue a project till the end?