hamster anxiety

Question
I have had my hamster, Tawanda, for about 4 months. I adopted her from my friend Jenna who had bought her in one state and moved her to another state where she lived in a house with 2 cats.

Once I adopted her, she seemed to calm down from when she was at Jenna's, and she reverted back to being nocturnal.

I recently adopted a cat, and Tawanda seems to be very anxious. Our new cat is not a jumper, so we're keeping Tawanda in a room gated off, but I think she can still smell the cat. The cat hasn't gotten close to her, but maybe she's just naturally afraid of her or maybe she's scarred from something that happened with the cats at Jenna's--I know they harassed her a lot. She's still nocturnal, but she seems jumpy. She's normally very sassy, but she's acting very cautious and moving around a lot.

Is there anything I can do to calm her nerves? Perhaps I should put lavendar or another strong-smelling herb near her cage so she can't smell the cat?

Answer
Just like any animal with a natural predator, your hamster is being very cautious, this is normal for a hamster.  The hamster has such a good sense of smell that even lavender will not prevent her from detecting the cat.  You should provide extra hiding for your hamster if she seems uneasy.  The type of housing may also play a crucial part in calming her down.  I would house her in either a sturdy plastic enclosure or I recommend an all glass terrarium with a secure top.  

Cats will be cats and even if you believe your cat not interested in the hamster, you must always plan for the worst case scenario.  Always make sure all the items in your hamster cage are high enough for your hamster not to easily climb atop and try to escape.  I always use glass because hamsters can chew thru plastic given plenty of time.

This is all the advice I can personally give you.