I had a toxoplasmosis scare at 9 weeks - I was in a right state. I won't bore you with the details but I did a lot of research and read all the stats - the chance of you getting it from a single exposure to rare meat is small. The chance you are immune is very high. The chance of it harming the baby even if you do get it is not all that high. All in all, don't worry! Go to the midwife when you can, explain everything, and you can get a blood test to show if you are immune (your blood shows old antibodies so they can tell the difference between old and current infection).
If they think you weren't immune and have been infected, IIRC there are still things they can do to reduce the risk of it affecting the baby.
I was immune. They told me you would almost certainly have already had it if you have been a habitual rare-meat eater, if you've had cats, or lived on a farm.