Congratulations firstly.
Rubbish that you can't BF when you are pregnant! Although, in some cases (if you have a history of miscarriages or other problems you may be advised against it by some doctors). I was breastfeeding when I got pregnant (planned) and I carried on feeding. Difference was that my LO was 18 months old. He ended up self-weaning when I hit my second trimester (end of third month) - just decided one day he didn't want it anymore. Could have been that my supply had gone (as is common I think at the end of 1st trimester) or tasted different, or he could have just been ready anyway regardless of the pregnancy.
Remember that you will obviously have to increase your calorie in take too. You need an extra 500 cals per day approximately when breastfeeding (if you don't want to lose weight really) and an extra 300 cals when pregnant - so you'll need to add some healthy snacks in there too to help with your supply too.
As someone said, there are plenty of women that do Tandem Nursing - nursing 2 kiddies at the same time - there are books on it. Something to seriously think about though and make sure it's something you really want to do. It wasn't for me personally, that's why I was actually pleased when DS weaned himself (I was dreading weaning him so he made it nice and easy!) Nursing a newborn is very fresh in your mind for sure, and you need to really think whether you could cope with feeding another baby too. Many people love it and do it successfully - and I say good for them - it's a very personal decision for you and your family.
But YES - you can breastfeed when pregnant for sure!
