Right so the important thing is to be sure what you want to do. If it's having the baby then go ahead. From what you've said about the father he's a pretty despicable, unprincipled, unreliable type so you have to expect to be on your own. So do what you want to do and he'll have to put up with it. Do not be influenced by his lack of empathy for you or his selfishness. Just give him the news simply, broach no argument and continue with your plans. If he decides to offer support, financial or other, good but it seems a long shot.
You need to make plans. It seems that your family will support/help you financially. Adding up the months, it seems as if you will be giving birth mid Autumn term if you go ahead with continuing your education next year. You may want to consider taking a year out , many people do for various reasons. Your uni will have met this situation countless times before and will no doubt make suggestions to help.
There are a lot of positives in this, you know. Having a baby is a wonderful thing. You will give a lot of pleasure to yourself and all your family. I've yet to meet anyone who is not tickled pink at having a youngster in the family. They'll all be fighting over who can look after her/him.
What seems like a terrible problem now will seem like a joyful serendipity in no time.
I knew a girl who had a baby in the Sixth form, she went to Uni , got her degree , fine.
Another friend of my mother's had her baby during finals for medicine. Didn't stop her being first in the year and going on to have a very successful career in Public Health.
So think positive. plan and you'll be rewarded by having a great addition to your family. All of us are faced with unexpected situations and challenges. The point is to it your best shot, just get on with it and you'll be rewarded over time. Good luck.