Milk of magnesia..

Hey! I know this is a stupid question, but I'm honestly curious. So I take milk of magnesia about every month when I get stopped up. Well, I usually take 4 tablespoons, but I ran out today which only gave me 3 tablespoons, Should I still take it and expect it to work, or should I just wait until I can get a new bottle in a few days? I also took a fiber supplement today as well.