I'm sorry to hear your dog isn't feeling well. The bland diet and pepto regimine work best if the intestinal tract is "emptied out" before starting these, sort of like starting from scratch.
For now, don't feed anything for 12 hours, but do allow water if she'll drink. (If not, she can always have some unflavored pedialyte). Then when you do feed, give that bland diet like boiled chicken or boiled hamburger meat with white rice (1:1 ratio). No treats, and don't let her eat grass either. Continue this diet for a couple of days as the stool firms up. Once firmed up, gradually go back to the regular diet over the course of a few meals.
Correct pepto dosing is here if needed:
If she's acting fine otherwise, try this, and if not clearing up in a couple of days, you'll want to make a vet appointment then, as an antibiotic may be needed if a lot of bacteria is breeding in there.
Best of luck, and let me know if I can help further.
I would bring her into the vet at this point, as she's displaying symptoms of fever or some bad discomfort (trembling). Parasites like giardia cannot be ruled out from one stool sample checked, but usually metronidazole is prescribed to help with intestinal bacteria and also helps kil giardia, so may not be necessary. However, since this diarrhea is fairly severe at this point and just leaking out, stronger medications will be needed. Without further diagnostics, you may not know what is causing this... it may just be intestinal bacteria building up from something not digested well or something bad being eaten, or could be any number of things systemically that are causing the upset GI tract. If still trembling, the Immodium isn't going to help with fever, so I suggest talking to your vet again as soon as you can.