J.S.
Go to your doctor - alone!! Yes, you're going to be a tired mommy with kids your age, but I found out the hard way after my third daughter that I shouldn't have been feeling as bad as I was.
I thought I had postpartum depression! I was so run down, emotions were out of whack - I cried about such silly things! I realized that I didn't want to go do anything with my kids whereas I usually take them out to the store, down to the sound, or to the library, etc.
So after my sister and close friend said, yes, they thought I hadn't been myself also I went to my doctor and found out that my Ferritin levels (stores of iron) were virtually non-existent, and my Thyroid had completely stopped functioning!! After 4 days on thyroid medication and 4 Ferrasorb pills a day, I was already feeling like myself again!
Now, you might not have such a dramatic story, but if there is something physically wrong, you don't want to ignore it because it will wear out the other organs that are trying to compensate for what's not working, and because it leads to emotional distress. Find someone who loves you and spill your guts. I didn't say anything for a long time, but when I finally told my sister and friend how I was feeling they were so helpful! They listened, sympathized with me, and helped with the kids when I needed a break for an hour or two.
Take care of yourself so that you are fit to take care of your little ones!