HIV transmission from cut

Hi,

I have been confused about a lot of things and information regarding the transmission of HIV that is present over the internet. Most of it is sometimes confusing and scary. Some sites make you scared about every little incident, while some just say "NO RISK" to almost all situations.
I've thus come to you to seek help and I believe that you would provide the most concrete/authentic information that is present with respect to HIV and its transmission.
Also, I would like to thank in advance for the work that you people are doing and the help that you are providing to people like me.

I live with a person who is HIV+. I share a household with this person. Now, I've had a few scares in the past and am worried about a few things right now.

Yesterday, I came home and went directly to the kitchen to eat food. Accidently I cut my hand from something. I do not remember exactly with what I cut my hand, but most probably it was the kitchen knife that was lying on a slab on the kitchen. I forgot to check whether there was blood in the knife or not. But now this incident has started to worry me as I heard my friend saying that he had also cut himself with the knife. Now, two more things that I can tell you about this incident are:

1. The cut on my finger was very small. In fact it did not bleed much, but blood was visible through the cut and it pained (like when you cut yourself). Also, if you squeezed, then blood came out. It was a small cut.
2. The knife had been lying untouched for atleast 5 minutes.

Was there a risk of transmission...? Should I get tested...?
I tried to read about this extensively over the internet. Some sites say that there is a very real risk of transmission in these types of cases. Others, however, would classify this under an environmental risk and hence state that the risk was essentially zero.
Was this an environmental risk. If yes, then why are people always warned against using sharp instruments.
Why should one not share razors/toothbrushes with someone who is infected with hiv...?

Also, a few days ago I got another small cut on my leg. I just do not know how I got it... it just was there... could this be a route for transmission. Also, I live with this person and also perform household chores with this person. Sometimes I may hit/brush against some object and injure myself. The other person may also have just injured himself with the same object... as it happens when you're moving something heavy etc. How much risk of transmission would be there in those cases.
Also could you please elaborate your answers just a little... beacuse most of the sites just answer that HIV is not spread by casual contact without addressing the particular situation.

Specifically, should I get tested for this knife cut incident.

Thanks in anticipation,
some.person