26 weeks pregnant

Hi, last Tuesday I was taken ill in to hospital with food poisoning, it was pretty bad and I passed a lot of blood from my passage, I still haven't felt 100% since and my bowels are not quite back to normal. I'm still getting a lot of cramps. I'm not sure if this is relavent to how I'm feeling now but since I woke up this morning I've had a lot of heavy pressure in my lower stomach and back and my legs are feeling the heaviness also.

Is this pressure normal at only 26 weeks pregnant? I heard you feel a lot of pressure when your almost due to give birth and I'm worried I'm going to go into early labour, or could it be due to the about of sickness I had last week, or is it just plain normal?

Thanks