tired 15w4 days

Maybe I'm just old. I am 34 and get a burst of energy in the morning, but by 5 I am done. I have a 5 year old who is mostly independent, but by the end of the day I am spent. I feel gigantic. I have a LOOOOOONG way to go. This is going to be a miserable 5 months the way I feel right now. Tell me I'm not the only one. Please tell me!!!