I am going to be very honest here:
It all comes down to how strict your parents are, whether they grew up in this country, and how embedded they are in the 'community' and their standing within it.
If they are very strict, care about what everyone says, then they are likely to disown you for bringing shame in them. You are unmarried (they will not recognise your nikkah because it was not witnessed by 2 Muslim men), you are pregnant and the man is a convicted criminal in jail. For them, this may be one of the worse things you could have done. The only way for them to save face is to cast you out.
If they grew up in the UK, are more liberal and don't care what other people think, they will support you through this but the convicted criminal father of their grandchild will be very difficult to overcome always (this is true regardless of whether you are Pakistani or English).
It depends on the Pakistani society you are from. Regular Pakistani society would shun you but in high society in Pakistan with your parents support, you'll just be a topic of gossip and the issue will be the father of the child being a convicted criminal. No one wants this for their child. How is he going to support you?
I think you said you are 30 weeks pregnant, you have left it very late to get support, sometimes people need time but you are giving them an ultimatum, which never goes down well.
I am not sure why you lost your job but you need to get another one ( working from home?), so you can support you and your baby if you font have your parents for help. You chose to have this baby, it's your responsibility to do the best for that baby.
Finally, chat rooms are helpful for advice but this is very serious and you need to speak to a trusted relative or family friend.
Good luck.