When I meditate for longer time, like half an hour. I feel like I am being moved by my mind in a certain direction, what is this feeling and how to avoid or remove it?

I think the mind has a natural tendency to wander during longer periods of physical inactivity. All you need to do is acknowledge the path your mind is trying to take, make a note in your mind about it, and recenter your thoughts on your breathing.

Meditation is simply being mindful. Which means observing your thoughts and feelings pass by from the side of the road without chasing any of them. So instead of trying to stop just observe and when you find yourself distracted, gently bring yourself back. This is not easy and hence practice makes perfect!

A certain direction? Is it a comfortable place you find yourself in? if so I'd say you are lucky! I try not to analyze, just notice, the go back to the breath. For me, shorter meditations work best, then I can do more frequently.

Think of meditation as a way of sleeping while being completely conscious and like sleeping you most of the time go to someplace peaceful to rest in a comfotrtable position. While you meditating you should try not to move and try not think of anything besides the voice of the instructor or your own voice (most of the time this should be the one in your head) to get you though the period of meditation. And if you ever think of anything else or even start to sleep just think of the voice.

You should try some breathing exercises like firstly counting like 1,3,2,4,3,5,6,8,7,9,8,10 and then focusing on three consecutive breaths and then repeating. This will greatly increase your focus and will also stop your mind from wandering elsewhere.

I am not honestly sure. I usually only do 10-20 minutes and I have never had that feeling. What kind of meditation are you doing when it happens? Perhaps it is the type and you should do smaller times of different kinds if you want to do a longer session.

Is it only there when you meditate? What happens when you stand and have your eyes closed? Why do you want to avoid the sensation? Does it make you feel sick or nauseous?

This should be normal because when you meditate, you are generating something known as energy and the energy creates vibration. I personally think it is not the mind that is moving the body, it should be the energy in the room that is attracting / pulling you towards the direction. I normally just leave my body and mind as it is during meditation and didn't make any adjustment because in meditation, I believe we should be embracing the "now" moment, unless if your mind wonders then you should be acknowledging the thoughts and refocusing it back to your breathing. Hope this helps.

It's nothing to worry about. It's the nature of the mind to wander to whatever it believes is most pressing for you to address. This wandering mind, sometimes called the monkey mind because of it's tendency to jump around, is the reason we meditate. Meditation gives us an opportunity to remember that we are not our thoughts. We can choose our thoughts. If you don't like the direction your mind is moving in, then you can easily direct it back to listening to the sound of your tidal breath as you slowly inhale and exhale, repeating a mantra, or a positive affirmation. Just relax and notice the movement of the mind from memories to future plans and back again while being present in your body and breath in the now moment.

Just whenever you notice it, acknowledge and take yourself back to counting your breath. Keep this up as many times as you can. Notice how many times you are bringing yourself back to counting. There is not right or wrong here, just some days we have more thoughts or more active triggers in our thoughts. Other days, it’s fairly clear and meditating feels like a joyful presence. Trying to avoid or remove is another kind of a thought that carries its own trigger.

Don't make attempts to remove these thoughts. Acknowledge them and let them float by and away from you.
Trying not to think about something allows it to remain present.
Concentrate on your breath and focus on breathing life into a single thing. That single thing can be a body part or it can be a visualization of something outside yourself.