I had a similar thing with my first, the scan showed he was slightly smaller than expected and we were monitored with more scans. We ended up being induced at 38 weeks and he was 5lb 2oz, so a bit small, and we had to stay in hospital for a couple of days to make sure his blood sugar levels were stable and then came home. He is now nearly 3 and it hasn't affected him at all.
They will most likely keep an eye on you and monitor the growth, but they really like to leave the baby inside for as long as possible.
Try to to take things a bit easier and make sure you eat regular nutritious meals.
Also worth a try (which seemed to work when No.2 growth looked like going the same way) is stomach breathing, so when you breath in push your stomach out so you are filling all your lungs. I used to lay in bed at night and breath like this, trying to get the breath right to the bottom of my tummy.
I'll definitely be doing this from day one with the next one as my babies seem to have small placentas than expected for their size.
Hope this helps smile