What can I eat to make sure I have a strong sex drive for this weekend ?

I am going to the beach this weekend with a new girlfriend and her friends and my girlfirend and I are going be having sex for the first time (what she said !) and I'm a little nervous because I have not felt very sexual the last 4-6 weeks possibly because of a natural anti depressant I was taking but just stopped or because I just turned 37. I don't think its my age though, I've always had a strong sex drive. So what foods vitamins or other things should I do to make sure I impress her in the sack this weekend.