my 'lil gal is feeling lethargic and weak

[kia23]

first time poster...

hi everyone!

i was googling "dogs feeling lethargic" and i found this site. i've got a 6 y/o shih tzu and 2 days ago she threw up 3x. her last barf had a whole denta-bone (a mini one) and a few unchewed treats. after that she felt really lethargic and just didn't want to move and stayed on my bed for hours and if she did get up, she'd go and pee and drink water. she's not touching her food and looks so weak. i don't think she ate anything bad coz she was so active not until she threw up her denta-bone. she has orangey leakage from her butt, not sure if that was a wet diarrhea and i don't think it's anal leakage coz it's usually brown. oh and she's in heat right now but she's usually fine when she's in heat and acts the way she usually acts.

we're going to see the Veterinarian later today...i'm just a bit worried. i wonder what it might be? does this sound familiar to anyone?