Is it possible for me to have contracted hiv?

Depends: To get HIV you need to be exposed to the body fluid of a person infected with hiv. Unprotected sex and sharing needles are common ways to acquire hiv. See this site for more info and if you have any concerns, see your doctor for a blood test. http://www.cdc.gov/hiv/basics/transmission.html.

HIV is hard to get: I need you to clarify or add to your question. The simple answer to the question is yes, of course. That is if you participated in any activities that are high risk for the transmission of hiv. But, the bigger story is that if one acts quickly after a potential exposure the infection can be prevented.