Glad you are OK, Terry; that was one scary encounter.
I was hijacked by 2 dogs 5 years ago while going 20 mph on my bike. I had no time to react because they came at me when I got within just a few feet of their hiding place in some bushes near the road. One charged to the left of me and the other to the right, and it was that one that got beneath my front wheel and down I went. They circled and barked while I lay on the ground for 10 minutes, unable to move. Fortunately, all they wanted was to make some noise and have some fun, but if they wanted to bite there wasn't a thing I could have done about it.
Finally, I was able to get up and seek assistance at the owner's house and make a phone call. He was blind and hard of hearing, so he was unaware of what was going on. My brother-in-law came and helped me get my bike back into riding condition, and despite a very sore right shoulder I continued on my 30 mile ride.
A couple of weeks later I completed a 300 mile 5 day ride that I had planned for for nearly a year. I did the ride because I found that I had less shoulder pain while riding. This had happened in early July, but it wasn't until late September that I had found out I had fractured my collar bone.
This past summer I had the same thing happen, except it was a single dog that charged me when I approached a hidden driveway. I had to stop suddenly and couldn't click out of my pedals, so down I went. I bruised a couple of ribs which took some weeks to heal, but I also strained some muscle tissue, and I'm still dealing with that. My biking season pretty much ended this year because of it, and I've had my other exercise regimen compromised.
It wouldn't surprise me if the dogs that attacked you have attacked others. Where I live (Wisconsin) if there is a history of one biting incident and they do it again that dog will be put down.