It sounds like you're blaming you child for your cold because he isn't washing his hands when he uses the bathroom. Pee and poo do not cause colds, that has nothing to do with you and your health....
Did you know that MS might be associated with being too clean? The body never grows the immune system so it becomes vulnerable and starts fighting itself.
Kids that go out and play in the dirt, don't wash all the time, maybe even go to bed dirty because they were out having fun and didn't have time, those kids are hardly ever sick. Their immune system is super strong because they didn't wash off all the stuff their system needed to build up.
Your body "heals" itself while you're sleeping. While you are awake your brain is managing your movements, eyes, hand coordination issues, what you hear, your senses, it regulates your heart beat, processes the foods you are eating, your brain works very hard while you are awake.
When you go to sleep you are paralyzed. You dream, your brain is working through issues and figuring out the solutions you need. It is also running at it's highest strength. ALL the brains processes are working on things. Like fixing wounds, dividing cells, repairing damage done by disease, building your immune system, and fighting off illnesses.
So if you're not getting enough rest your body is vulnerable. It's a high risk for you to not be taking care of yourself.
I suggest you find a Mother's Day Out and take little one for at least one day per week. Go home, take a nap, set the alarm so you don't oversleep when it's time to go pick her up.
Colds often start out from allergies. Don't take an antihistamine. Take something like Sudafed to wash your sinuses out. The runnier the better. The dried up mucus that an antihistamine gives you is a breading ground for infection and drainage that can even cause pneumonia.