I have been at my job for a year and a half, and for the last six months has been a living nightmare.
I have been given verbal warnings because " I don't stay in my seat enough", because " I have spread rumors" (which was never true) and I was written up today because I don't have a business maturity.
I am wanting to get pregnant and have another child since I have established a job that I like, but my boss is making it very difficult.
He has made it a point to make sure that he finds every little detail wrong, and doesn't come to me to ask questions, he finds a co-worker and then has them to ask me questions.
I have complained about him to my Plant manager, and to Human Resources, but they tell me it is all in how I perceive things.
Everyone (including myself) has very low morale, and I have 3 co-workers that are leaving in a few months because of the situation that is going on.
Would it be wise for me to have a child in this situation knowing that I am on the boundaries of getting fired?
I have placed bids in for different jobs, in hopes to move quickly, but I have not received any answers from them, and my boss has final say so to let me move.
If I were to get pregnant, could I be fired from my job?
If I were fired could I draw unemployment benefits?
Any response would be greatly appreciated.

You cannot be fired BECAUSE you are pregnant. But being pregnant does not protect you from being fired for unrelated reasons.

Whether or not you could get unemployment if you were fired would depend entirely upon whether you were fired for a reason that disqualifies you for benefits or not.