I am getting so tired of my manager all I want to say to him is no.
What do you think they would say ?
Your company should invest more in you. You are a valuable member of our team
It is good to not want to be exploited at work. You should be truthful but know it might have some consequences.
I'm just so tired of it all, everything just makes me feel so numb. I am sick of this job.
If you feel overworked and under appreciated at work it might be time to find a new job. You already have a good set of skills that can be useful. Have you tried looking to see what jobs are on the market?