parasites are insidious. They can cause all kinds of low grade symptoms like bloating, headache, body aches, diarrhea or constipation... the feeling that there is "something in there"... or you may be totally unaware you have them.
If you have never done a parasite cleanse, or it has been a long time, chances are you need one. Of course you can be tested for parasites (usually a stool analysis), or just go ahead and do a general cleanup. There is a good parasite forum here at curezone with all the info.
It is always a good idea before doing any other cleansing to be sure parasites are dead dead dead!