Please help!

23/4/08My dog started having dirrhoea. Actually, Soft stools. W
asn't exactly watery. That day was also the start of my house renovations all that. You know, drilling and scrapping all that.

25/4/08. He started having soft stools with abit of blood. The amount of blood increased eveytime he pooped. Due to house renovations, we brought him along with us to a vacation house.


26/4/08. Dirrhoea starts. As in, his stools has no shape. Really quite watery. His stools has a weird smell too. We have brought him back home alr. But his bloody dirrhoea persisted.


More details about my dog:
- 4 months old toy shih tzu.
- Had his 3rd jab alr.
- Is on anti-biotics for his rashes and flu.
- Active as usual.
- Drinks normally.
- Urine normal.
- Appetite abit different. (Poorer. Eats only when we hand feed him.)
- Dark reddish brown stools.
- We did not change his diet.
- Rumbling stomach.

Isit due to stress because we keep changing his environment.?
What can we do to make him feel better?
Is immediate medical treatment needed?