The social worker will assess the situation but the primary goal for everyone will be to return your children to your care if it's safe to do so.
Be honest with the social worker about how you have been feeling and the support that you need. Have you seen your GP for your depression and are you taking medication? There may be some courses that they can put you on to help you improve.
The threshold for removal of children is that the children will (or are already) suffering significant harm. You do not need to be a perfect (or even good) parent although of course this should always be the goal.
One instance of hitting on the back of the legs is cause for concern but it is not illegal (if you are in England) where it amounts to reasonable punishment, therefore it's a subjective test and circumstantial.
Feeding your children pasta for tea is not neglect. Neglect might be not feeding your children at all, feeding them poorly, not providing them with a clean environment or clean clothing, not ensuring that they are attending dentist appointments or relevant medical appointments, misusing drugs/alcohol etc.
You need to prepare to be honest with the services you will encounter, and show genuine willing to overcome these struggles.