In need of a pep talk

I have a 6month old and a 2.5 year old plus working a full time 50+hour work weeks. I feel so incredibly exhausted right now I’m in a bit of a down place mentally not bad bad but just feeling like I’m streatching myself out so much to make everyone happy and make it so they don’t stress yet feel like I could be doing more. I am so tired I can barely keep my eyes open at work and I just want to cry because I have never been this exhausted in my life, not even in those early sleepless nights. I just feel like we are in such a growing period in our home that I barely feel like I get to see my husband at all, he does a lot around the house and I am incredibly lucky for that but I always feel like I could be doing more even though I’m doing so much, is this mom guilt? How can I wake my self up? I’m breastfeeding, so I don’t really drink much caffeine, but I just need to get myself going and awake and keep myself from crying!