I am sorry to hear that.
I assume you know about your UF (ultrafiltration) limit? For a 110lb person or 50kg it should be:
10 ml/hr/kg * 50kg = 500 ml /hr or half a liter per hour. If you are in center, you are usually under a time constraint to hit your dry weight - which is a poor way to dialyze. That means you should have been dialyzed for more than 5 hours in order to get 2.5 liters out - but I assume they didn't follow that.
This UF limit should also be age related, that is if you are an older person, you should adjust it downwards.
Rapid fluid removal during dialysis is associated with cardiovascular morbidity
http://ihatedialysis.com/forum/index.php?topic=20596.msg343443#msg343443