Unless your family has a history of sever allergies, you should be fine eating peanuts or peanut butter. If you, DH, or a close relative has had a problem with any of the common allergies, some research suggests that you should avoid those (wheat, eggs, peanuts, etc.) during pregnancy. We have no history of allergies and I've been encouraged to eat peanut butter as a good source of protein.
There is a significant risk of lysteria infection in lunchmeats. However, by heating the meat through, you can kill the listeria and it's perfectly safe to eat (putting aside the nitrate issue-- that's your own decision to make). If you have a microwave at work, heat the meat for 30 seconds and, from a health care provider perspective, it will be safe to eat.
Some other common foods you may want to avoid are tuna and predatory fish (for mercury content), alfalfa sprouts (also for food-bourne illness concerns), and of course anything with alcohol or excess caffeine. Take it all in stride, though-- a little "forbidden fruit" now and then likely won't be terrible for you or the baby, but moderation is key!