I woke up early this morning and heard a female voice say my name and 'go'. Is this God's voice? It was a familiar voice...
One of the keys, I think it would be fair to say, would be to be absolutely sure you heard the voice.
Second, be absolutely sure that it did not, for example, come from someone in the house or place you are staying.
It's not that I do not believe God speaks in an audible voice sometimes. I do believe that. I have heard Him speak to me very clearly. However, it's still good to be sure of these things, because there's always that possibility -- but if you have discounted that possibility, then you would have to move on to the possibility that it was the Lord.
The fact that it was female, I'm not sure what I would make of that. The Lord can easily assume the persona of a female or female voice (for example, in a dream, you might meet a woman, and it might, in fact, represent the Lord). So the fact that it was female does not throw me. There would, though, likely be a reason that it was female, as opposed to male. Here is one possible reason (I doubt it's the main reason, but I'll just mention it). Sometimes, the Lord may assume a persona for the sake of approachability and reachability. In other words, we may feel more comfortable relating with one or the other, and the Lord wants to make the communication as easy as possible, so that you don't miss it. If the presence of a man raised a flag, then the Lord might change the persona to a woman, so that you could easily receive it. Obviously, there might be other possible reasons, as well.
Well, having said all this, the word you received was very short. However, that does not mean it was not God. I have receive very short words before from the Lord, and it was the Lord who spoke it. So now it's up to you to decipher what "go" might mean. You said the female voice said your name and then "go", so there was actually more to it than just the word "go". Obviously, that got your attention, as it would mine. Well, were you previously thinking about going somewhere? Or, is this a call to vacate and simply go away from where you were at the time? The actual meaning is open to interpretation. I think in large part it may depend on what you had previously been thinking about doing.
In situations like these, context if usually the governing factor. Were you thinking of visiting your mother, but were hesitating and making excuses not to go? (This is just an example, of course! Fill in the blanks with any other possibility.) Well, I don't want to put you on edge thinking about the possibilities, but one thing seems rather clear, if this was the Lord, then there is a puzzle that needs to be solved. Where or to whom or in what direction should you go?
PS. I personally am extremely flexible when it comes to the Lord. If I heard a voice telling me to "go" I might take it as a sign to immediately go for a walk, and bring some evangelistic tracts with me. Then, as I walked along, I might pray to the Lord, asking Him to lead me to the right person. So there are indeed many ways to think about this one.
If you remain unsure about the meaning, I would take it to prayer and go over all the possibilities with the Lord on your knees. I'm sure He will show you what exactly He is getting at in the process of time. Surely, He gave the word for a reason, so you can trust Him to explain it to you, as you take it to Him and seek His counsel. I think you're doing the right thing in posting this, and I believe the Lord will definitely work through this means, and perhaps others, to help you understand His end intention in all of this.