I am currently breastfeeding and want to get pregnant again. I am yet to menstruate so is it possible I have been ovulating? Can I "bring on" periods?

Breastfeeding. Breastfeeding every 4 hours during the day and 6 hours during the night makes ovulation almost impossible. You cannot bring your periods while breastfeeding. It is the way of nature arranging things so you can help your baby grow. Once you start ovulating the milk production will stop soon.
Possible, unlikely. You can ovulate even if you haven't had a period, and your doctor may be able to give you something to "bring on" a period if you are making enough estrogen now to make a uterine lining, however, it is less likely to happen while you are breast feeding.