Please help me as it feel like I am losing my mind!
We have an 11yo dog who no longer goes on walks. She only toilets in our garden. We are surrounded by cats and I think foxes visit at night so as well as my dogs poo, I am often always cleaning up the neighbour's cats poo and what I think might be fox poo. I am a SAHP, neighbours work and I don't think they notice the poo. Anyway, it's always by MY house (no cats) 
The bigger problem is that I think I've noticed tapeworm in the poo quite a few times. My dog is wormed regularly with Drontal but the gap in needing to worm her is getting shorter. I used to do it every 12w, then 8 weeks then last time I needed to do it after 4w. It's been 4w since she was last wormed and I think she needs worming again because of what I was today. There have been poos on the garden with what I think are worms in that could be from my dog: right size, shape colour. But then the other day there was some out front that was identical that definitely was not from my dog.
I'm so confused. I keep the house clean especially as I have 2 young children and vacuum every day, including the dog's bed. I also flea her every 4w. Last time I wormed her after 4w, it seemed to really upset her stomach; she had diahorrhea and very smelly wind for several days.
What should I do? Should I worm her again or wait to see a few more poos that I know are hers? She poos at night so I usually clean up in the morning so it's difficult to know if it's hers.
FWIW, what I noticed today was loads of tiny, white seed-looking things within a sloppy poo (sorry, that was gross).
Please help.