Typically if something is working, you should not change it. When the weight gets heavy, your first temptation is going to be to make a change. It's okay that it's hard. Let it be a little hard.
Age/weight/sex?
Can you briefly explain why you can't train with at least a day of rest between each training session?
Can you fill out what you do for the other lifts as well on M/Tu/Thu? It's not clear to me, based on your description.