I don't think it's the dogs. It's probably being on your feet at work the whole time. When you work you're on your feet and when your home you probably relax more. Try taking it easier. It's normal to spot throughout pregnancy. If its heavy bleeding then it isn't normal. It's not uncommon and its not unheard of for women to lightly bleed throughout pregnancy.
I'm 15 weeks and have been having bleeding. I'm told mine is a subchronic hematoma, but they couldn't see where it originated from on my ultrasound. I've found mine seems to be better when I'm taking it easy vs working and on my feet a lot. I hope it clears up for you!
I'm 9 weeks...and I have a large Subchorionic Hematoma. I have had 2 very heavy bleeding spells in the last week where I've saturated 3 pads in a very short period of time. With each bleed I was sure miscarried...but the baby still has a very strong heartbeat. Thank God! My doctor says this does increase the chance of miscarriage but that there are plenty of women who go on to have a perfectly healthy baby. For now, I've been off work for a week, try your stay off my feet as much as possible, and pray multiple test a day.
Good luck to you...I'll keep you in my thoughts and prayers.