Does it sound like im in this relationship because im scared to let go?

Ok so im 18 and with my partner, I used to get excited when i saw him i used to feel good when i was with him and feel emotion. I now don't feel any emotion for him accept when im angry because he does something thats made me angry. I get cross with him a lot and i just think that maybe the spark has gone out of the realtionship and i really don't know wether to let go or not. I don't feel its working anymore and feel like i have nothing to hold onto. I feel the only reason im still with him at the moment is because im scared to let go incase its the wrong decision and i know it would hurt him. But theres not only that to think about, i fell pregnant in march this year and lost the baby at 6 weeks due to miscarriage, ive seen been caught again again by failed contraception and i though that it would be happy like last time and i would want to keep the baby, however this time ive been very very ill getting virtually no sleep at all with sickness all the time not being able to eat much ect. I have exams soon and now im not sure its the right time to have a baby. I want to go on to uni, but how do i make a decision wether to keep the baby when im not sure if i want to be with the father? I have to choose out of 4 lifes at the moment, one with a baby and the father one with the baby and without the father, one without the baby and with the father and also without the baby and without the father. I feel like im in the relationship for the sake of it, like its become a habit, How do you choose wether you want to be in the relationship and wether to keep the baby or not. I have pre-natal depression and so thats playin a huge part in deciding as i really don't feel i can deal with this any longer. Please help and no nasty answers please