Hi M.,
Bringing your baby into bed with you is not a bad habit. As you see your are getting some extra sleep. The baby will not be with you in bed forever--after all she has to leave for college! LOL! Many cultures co-sleep. I suggest you read any of the parenting books, especially Nighttime Parenting, by William Sears, MD and Martha Sears RN. Dr. Sears is a pediatrician and he and his wife have raised about 8 kids of their own. You may also want to check the research done by Dr. James Mckenna on co-sleeping.
As to your milk supply. Usually at 3 months, moms find their breasts are softer and think that they are losing their supply, which is not the case. First, you need to rule out---have you started any new medication? Hormonal birth control can also deplete milk supply. Are you pumping often enough during the day. If you work a typical 8 hour day and do not see the baby to nurse, you should be pumping at least 3 times per day. Do you have a good pump? You need a professional pump, such as Medela Pump in Style or Ameda's Purely Yours. These pumps are good and mad for you to succeed. Anything else, is not good, will not keep up your supply and can actually cause damage to your breast tissue.
Also, when you are home with the baby, you need to be nursing, not pumping.
As far as herbal help, I suggest a combination of Blessed Thistle and Fenugreek capsules. Three of each, three times a day as recommended by Dr. Jack Newman (http://www.breastfeedingonline.com/24pdf.pdf).
Hope this helps.
G. T.