A.P.
I think Jenny said it best....Fenugrek, lots of water (I am drinking 3-4 L per day), good sleep, more frequent pumping and try not to stress. It is a state law that your job needs to allow you adequate time to pump at work. I think the law is on The La Leche Leauge website.
If you have a madela pump get a car or battery adapter. I find that I can use my cover (boob tent as my husband calls it) and pump while I drive to and from work. This gives be two extra pumps.
When you do find time to pump at work are you worried about getting back to work? This might be hindering milk flow. Try to relax as much as possible.
My son is 7 months old but when he was 4 months I was pumping between 3-5 ounces 3 times at work and 1-2 ounces 2 times in the car and 4-5 ounces at night after he is asleep.
Pump as much and as long as you can. After you have pumped let the pump continue to suck for an extra5 minutes. This stimulate more milk production. It all works off supply and demand. The more you pump (or baby sucks) the more milk your body will make. I always stress about not having enough too but it always seems to work out. I remember when he went from eating 4 ounces at a time to eating 6 ounces. I thought for sure I would run out but my body just produced more. Also soon your little one will start eating cereal, fruits and veggies. You will need less milk then. Follow the steps above and remember to breathe and everything will be fine.