17 weeks pregnant and wanting to stay fit and practice healthy eating

My baby was born in May, but I only gained 5 lbs. from my pre-pregnancy weight to 2 weeks after he was born. I mostly kept up my normal healthy eating, allowed for more full-fat versions of things than usual, and I was still running as much as felt okay. I actually didn't find out I was pregnant until I was 20 weeks, so I was definitely just doing my regular thing (though I was hungry more and running was getting harder--didn't recognize those as pregnancy symptoms!). I think some women just start in with the "I'm eating for two!" and the "what the heck -- I'm pregnant!" and they feel like they can't/shouldn't exercise. Yeah you're eating for two, but one of you only weighs a few ounces. From what I've read, you should increase calories by about 200-300 a day, which is really just an extra snack or so.