Stress less, sleep more! If it helps, my son was 3lbs 4 oz. He could barely get his fingers around my husband's index finger. Fast forward 3 1/2 yrs, and he is now just as solid as a keg of nails.
Your girl will be fine, probably have a pit stop in the NICU, and just do the best you can between here and there. After a certain gestational date, the Dr.s are mostly guessing anyway. They want to give you any bad news first, but don't really hand you a heaping plate of hope, which you need now more than anything else.
She might be small, but she'll show her colors and personality, real quick. Love and adore her. Don't fret about size (is that womanly advice, or what!), and just listen closely to what the Dr.s tell you. Washing hands will help reduce the risks of infection. Easily done. Let her sleep when she's tired, and watch how much food she's taking down. All easy, all simple steps.
And pray. Not the bargaining type, just the, "okay, this is totally unexpected, what do I do now?" kinda prayers. You'll feel it in your gut what is right, and be able to move confidently forward. Hang in there 'til then, and I hope you can enjoy a big heaping plate full of hope. :D