Should you be emotionless during meditation?
Meditation doesn't necessarily require you to be emotionless. It also doesn't require you to be thoughtless. Meditation doesn't really require you to be anything.
You are who you are, and if in the moment that you are meditating you are full of thoughts or emotions, then that is who you are, and there is no requirement to stop being yourself in order to meditate.
On the contrary, actually, meditation itself can help reduce those thoughts and emotions. This is one of the main reasons people start a meditation practice in the first place, to be able to better control their minds and to handle these situations where they are full of thoughts and emotions, especially when they leave them incapable of making decisions or going on with their day in a good and positive way.
If you are meditating and expecting the practice to reduce your emotions, and it is not happening, this could end up making you more stressed than you may have been in the beginning. This is why meditation shouldn't be done with solid expectations of a given outcome.
You may begin meditating expecting to be enlightened after just one session. This probably won't happen, but what may happen is that you will believe that meditation doesn't work and is not for you, and you may just give up on the whole practice completely.
It's strongly recommended to not have these kinds of expectations when starting to meditate. Instead, just meditate. Let things happen in their own time, and as you keep a constant practice, you may start to notice the effects it has on you.
As all good things, meditation takes time and patience.
I don't think you should be emotionless. I think that, in a way, you shouldn't be anything, you should just be there in that moment.
By that, I mean, you should just let what ever emotion that comes up be, and just watch it and understand it. Same as thoughts, you shouldn't be fighting your thoughts during meditation, you should just be watching them, not trying to alter them or control them, just letting them be until they eventually drift off.