Loving somebody or even having a child with them doesn't necessarily mean that they're the right person for you to spend the rest of your life with. The fact that you're asking this question suggests to me that you might have some niggling doubts in your own mind which arn't just connected with a wedding. Only you know the answers to some of the following questions you should be asking yourself:
Do you trust him implicitly in all things?
Is he kind and considerate?
Do you work together and pull together as a team or are you always arguing about something?
Is he a good father?
Does he treat you with respect?
Are you good friends?
Do you share similar interests or are you not compatible?
Does your heart give a bump of pleasure every time you meet up again, even if it's only after a day's absence at work?
Can you imagine how you would feel if he was no longer in your life?
I think it's significant that you didn't feel you loved him enough or felt secure enough about your feelings to marry him when you first discovered you were pregnant. Ask yourself what were the reasons which made your hesitant then. Has anything really changed about your feelings of uncertainty? If not, perhaps you still shouldn't be rushing into a marriage.