Why is my available balance in the negatives?

i have a santander bank account and recently deposited a quite large sum of 拢5000 last Monday, i was expecting it to be able to withdraw it on the following Wednesday but when i went to withdraw it said my current balance was 拢0.32 and my available balance was -拢4999.68, does this mean i owe them money?? if so then thats LAME but i'm really confused right now : (|||Now a days it is the practice of bank to show the actual balance that can be withdrawn and the balance accrued which include the amount of cheques deposited and yet to be cleared from the related bank.Hence you have to wait for clearings that may take some couple of days.|||No it means the Deposit has NOT cleared. It can take 3 to 7 business days