I was confused because I did not know if ur personal project had sth to do with ur work. Since u have asked for leave on ur birthday and want to relax ur self, it is not logical that u will sth related to ur work at the same time. But if it means ur self-designed projects such as ur music composition or sth on ur hobbies, I think that would be more natural. Besides, I agree with Hunter, 进步 is not correct here. It is not a transitive verb in Chinese. We do not use 我们进步什么。Actually, we use 我们 使什么进步 or 我们完善什么，我们推进什么。So u can rewrite like this: 明天是我的生日。我向公司请了假，希望能利用这个时间放松一下，也抽点时间推进我的个人项目（丰富我的业余生活）。 words in the brackets are alternative. PS: Happy birthday!

“项目”在这里没错，但是“进步”作为动词时是离合词，是不能够带宾语的，所以要修改动词，可以用“完善我的个人设计项目“，这样就比较恰当了。