gettin into the childcare industry

Hello, i am currently studyin my level 3 dpp (havent got level 2, gone straight in at level 3). i work in a pre-school 2 mornings a week (I started just as a volunteer, i now work officially for one day then just go in as an extra on tuesdays when son at nursery) and i also work part time as afitness instructor for 20hours a week, been there for about 3 years. i dont enjoy the gym anymore and want part time in childcare as i am tryin to break into the industry but am having no luck. it's getin so frustrating, i have been apply and sendin cv's to local nurserys for about 9months and either get a no thanks or dont hear anythin. i thought my CV was good, but obviously i'm not. i just dont know what i'm doing wrong!
If anyone has any tips or advice for me it would be much appreciated.
kay x

p.s. i live in southend-on-sea, essex