breaks fluid deposit is empty and of course breaks pedal is really low,how is it

You have a leak in your brake system. It is unsafe to drive. Besides finding where the leak is and fixing it, you will need to bleed the air out of the lines before driving it. For info on where the leak is, look for a wet spot under the truck next to the tires. Also, see if there is any brake fluid trickling down the firewall underneath the master cylinder/vacuum booster. If you have never performed brake work before, you may want to bring it into a shop. I put a link here for shops within your area. http://repairpal.com/toyota-within-10-miles-of-los-angeles-california-90002