Help!! Sleeping probs!!

Hey. My little girl (just turned one the other day), who we have never had any probs with sleeping... Great with day naps and sleeps through the night,however ever since we hired a Nanny (for just one day) she has been terrible!! I know the stranger anxiety is at it's peak between one and two years old but I don't know what to do? She's still fine for night sleeps and goes done fine however it's her day time sleeps that she resists and screams blue murder!! After her feed she knows what is going to happen and starts getting all worked up. I go in resettle every 15 mins by tucking her back into her cot and saying "I love u, good night" and then walk out which seems to make it worse. We've got into a bad habit of picking her up after an hour of screaming and then she's fine. Then I pop out in the car and she falls straight to sleep as soon as I put her in car seat so clearly she's exhausted. So the last two weeks her only naps have been in the car. Because they aren't very long she's shattered by the eve which makes for a VERY grumpy bubba. Please help with any suggestions as I'm finding this crying out method is not working and it's stressing me out!! She was having two sleeps in the day prior...