Depends. Just being 'exposed' to lead does not mean that you will develop symptoms. The lead has to be absorbed into the system in order to feel symptoms. For example, just having lead based paint on your walls does not necessarily mean that you will have symptoms. If the paint chips are put into the mouth (as kids sometimes may do), then the lead gets absorbed and symptoms can develop.
Varies. If you think you have had lead exposure see your doctor and get a lead level checked, You may not recognize subtle symptoms.