How much bleeding is too much bleeding?

Lisa
I am 24 days PP and I had beryheavybleeding for 2-3 days post C-section.  I spotted lightly for another 2-3 days and then stopped bleeding. 8 days PP I went in to my OB office because I was having a lot of pain in my vaginal and rectal areas and my OB wanted to check for a Bladder Infection/UTI. Tested negative but was having a PP preeclampsia episode so ended up in the ER where I stood for 10 hours waiting to be seen by a Dr (some medical emergency - my Dr. even called ahead). The very next day I started bright red bleeding again. I thought maybe I just overdid it and it would settle down when I rested.  I went for a preeclampsia follow up on 1/6 and things were looking good, but they ran my urine sample for a UTI and this time it was positive. So I'm on antibiotics now.  I am not sure if antibiotics can cause more bleeding, etc.  
Anywho, for the last 3-4 days my bleeding has been significantly heavier and much more clotty.  The largest clot I have had so far has been about the size of a marble (shooter - the larger marbles). The bleeding is also bright red and tends to be a little more gushy (like period bleeding). 
I had a very easy pregnancy, but have already been to my OB three times in my first theee weeks PP. I feel a little ridiculous calling them about another issue just because I have no idea what is normal and what is not normal. I am also experiencing a sharp pain that comes and goes on my left side of my mid to low abdomin. Anyone able to give advise on this bleeding issue?