Pls explain

Today I tried option selling for the first time I sold 1 lot today, using 61k as margin. I have 10k free cash in my Zerodha account, but I am currently loosing 3k mtm. The issue is that the 3k loss is being deducted from the free cash; shouldn't it have been deducted from the 61k that was taken as margin? or do i have to always keep extra cash for loss?