I have just come off the anti depressant sertraline?

i was on 150mg, ive gone about it the wrong way and just come off the full dose,just stopped takin them. but i felt that was the only way i could do it.but now i feel moody,snappy,aggitated,anxious and irritable.has anyone else had simular?how long does this last?cos i dont want to be like this. its upsetting my husband because im always snapping at him,and i feel im being a crap mum to my 14 month old son