L.,
Breastfeeding while pregnant can be tricky. It works really well for allot of women, but for some it seems like no matter what they do their milk will decrease or dry up.
There are certainly things you can do, and you shouldn't give up unless you really want to.
Number one is to make sure you are nursing frequently enough (5X @ 15min+ each or more in 24hours is frequently recommended, although with the age of your child you should probably be nursing more than that if it's your baby's only milk source). Most mom's find that they can increase their milk supply by increasing the amount of time they spend nursing. Some mom's unconsciously reduce their milk supply by avoiding nursing due to sensitive nipples while pregnant.
There are foods and herbs that increase milk supply. You will want to consult with someone on the herbs, or at least do your own research. The foods in all cases are harmless and can help. Allot of women enjoy oatmeal, ;-)
A great resource for breastfeeding information: www.kellymom.com
Also of course there is La Leche League; local meetups and online info are always free.
I have started a myspace page that I will be using until my website is up and running. I have allot of breastfeeding info I trust linked to that page, and will have the pregnancy info up after the holidays.
www.myspace.com/freedommidwifery
Lactation Counselors and IBCLC's are very useful if you can afford them, but realize that La Leche League has people working for free with the same qualifications. The only difference is that you will have to seek them out and adjust to their availability. The group meetups are very encouraging for mom's, especially those doing tandem or extended nursing. It's hard to get support for these things in mainstream culture.
Good luck to you! I hope you are able to acheive everything you desire for you and your children.
F.