You do need to find a couple of other places to put her that are safe. It's a bit of a shock when they change so suddenly, and what you've been doing before doesn't work anymore... they keep us on our toes by their sudden spurts of development!
You aren't a bad mum at all, I think every baby has fallen of a bed of sofa at some point. You get caught on the hop, and that's nothing to be ashamed of, it's called motherhood!
But now you know, you can't carry on doing the same things and expecting a different result, or the bumped heads and lunging into space will continue.
She's going to be in this stage for a while now it is time to use the floor more, play mats, a jumperoo, a baby seat, high chair or other safe places.
If the floor is unsafe due to the dog then you need to change things so either the dog or the baby is portioned off at key times, like at feeding time.
I know some people have very strong opinions on play pens but used right they're great!
I had a baby Dan one that took up most of the lounge and was big enough for me to sit in too to do some playing and settle DS down in. I made it snuggly with a sheepskin rug and would use it just for 20-30 mins at a time so he didn't get bored or lonely. As he got a little older I set out different toys in it or strapped onto it, so it was a stimulating place to be and he liked to see what was new each day.
I'm confess I also positioned it so he could see the tv when he was a toddler and getting far too adventurous to be stuck in it - reserved for absolutely essential moments when I needed my hands free and it just wasn't safe for a marauding toddler with no sense of danger!
I'm telling you this so you can see that being a good mum isn't about being perfect, or having lofty ideals and standards to measure yourself against. Life isn't perfect and you do what's best at the time, and it's very important Not Judge Yourself Too Harshly!
It was a monster thing though and you could go for a smaller one that's off the floor (like a travel for) if you don't want to split your room into two. Oh which reminds me, they also do great barriers that are like fences with baby gates in them so you can literally divide a room into two if that works better from a dog/ baby space sharing?