Do you drink milk or indulge in other dairy products?Do you smoke?Are we talking your saliva is thickening,or you are discharging mucus frome your sinuses?Speaking of sinuses,do you have sinus problems?I dought you are allergic to the juice,but it is possible.Juicing does speed up the bodys ability to cleanse itself.Hopefully that is all thats going on here.Are you familiar with the concept of autointoxication,this is considered a healing crisis within the body.If you dont eat breakfast you may experiance this,a mini fast.When the body cleanses faster than the body can deal with the toxic load you will experiance a bad low energy shaky kind of feeling.Fasting can be a wonderfull way of cleansing and resting the body if done properly.What kind of juicer did you get?Good luck and happy juicing!!!