Safety Gate Fireplace

I am so nervous now because my toddler fell and hit her head on the back of my kitchen chair. The floor was not slippy and I would have never forseen this accident potential. I have capped my outlets, Safety Latches on cupboards, meds and cleaners are away from her and I have gates. I foam padded the block around my fireplace and foam covered piano bench. should I put a gate around the fireplace eventhough I do not use it or just cover it some more with foam floor tiles. I am so terrified of her having another injury. The first came at nine months when she split her lip on a coffee table. It was a small injury but this last one required 5 stitches and I feel so terrible. I have been depressed since it happened and find it painful to see her like this.......... I can't cage her but what more can I do to prevent her from hurting herself, toddlers are so full of energy and mischief.