Is she a true friend or is she speaking the truth?

Well, my first thought would be...

She's hooking up with multiple men and even getting pregnant by some random guy.  OK, that is bad enough.  But tell me HOW, exactly, does that qualify her to judge who is a good dad or not?  I suspect this slot has ZERO idea of what a good dad is.  Maybe if she had better role models she wouldn't have gotten pregnant by some random guy.

The fact that you are bothered by the suggestion that you MIGHT be a bad dad just indicates to me that (most likely) you specifically will make a much better dad (if you choose to go there) than her own dad was. 

As for whether you should finally cut her off...

It was never a serious relationship and now she's pregnant with some random guy.  Yeah, like ghost her.  Like, yesterday.  

I hope this is a genuine question. If it is you who got her pregnant, then take responsibility for the thing you have helped create. Be a man!

If it is a real question, and everything you have described here is in fact the truth, in that case: I hate to say it, but she could be looking at you as a potential resource for her and her child, and nothing more. Someone to help support her and her kid, while she potentially goes out and does whatever.

If I were you, I'd walk away from her, and never look back. Given that she got pregnant by some other dude, while she was seeing you, that should tell you right there where you stand with her.

Plus, it should obviously tell you about her character. And that is, she never cared about you, not one bit. It was never serious in the first place, and never will be. Remember: A person's actions, or lack thereof, will tell you more than their words ever will. Go by what people do, not what they say.

So before it goes on any further, just leave the situation. Her being pregnant and all of that by some other dude, and I hate to possibly sound like a jerk about this, but it is not your problem.