So tired

I am so tired all the time I’m afraid it’s getting in the way of my work performance. Or maybe I just want permission to not give 110% every day. I don’t know if it’s perimenopause or medication or just not caring or giving two Fs about work as much anymore. I find it so hard to stay motivated to complete tasks. I’m 40. This has never been a problem in my life. Please tell me I’m not alone in this struggle.