I've done it for years (not now bc pregnant). It's really hard at first, especially the first 5 days. But you'll feel AMAZING. Your body feels so clean inside. The first few days you'll have headaches and you might feel sad and deprived--but that goes away.
Now....
Eat HEALTHY foods. Some people switch to "frankenfoods" eating things like sugar alcohols (in things like "sugar free" candies). You'll never feel good or be healthy that way. Eat a ton of dark green veggies (these are technically carbs, but I imagine your doctor means foods like bread, rice, pasta). In a few weeks you'll eat a red pepper and it will taste so sweet and yummy.
Eat enough fat. Don't be afraid of fat, it makes your brain work. Not salty fat (don't only eat bacon!!) but have some eggs with mayo, or add some butter to your broccoli. You'll feel full and satisfied.
There is a great message board:
http://forum.lowcarber.org/forumdisplay.php?s=c04219f8156505a501ce491ff2b3b063&f=2
look at the Induction-friendly recipes for the first few weeks.
Plan ahead, if you do super well for two days then you have a slice of cake you'll feel horrible and feel like you can't do it. Eventually you can have "cheat meals" but stay clean for the first few weeks.
If you want the science, read Good Calories Bad Calories.