When we see a star in the sky at night what exactly are we seeing? Is a star a planet consuming hydrogen like our sun is?

A star in the sky is generally another sun... most of the brighter stars we see are much larger than our sun is; Sirius, for example, is a little over 8 light years away, and about 6 to 8 times the mass of our sun. While most of the stars in the Milky Way are red dwarfs, and smaller than our sun, they are still massive objects with at least 80 to 200 times the mass of Jupiter.

A few of the objects we see that look like stars in our sky are actually other planets of our solar system; Jupiter, right now, rises in the East a little before sunset - it's a brighter, yellowish star in the East/Southeast sky.

Stars are Suns. Large balls of Hydrogen Gas undergoing Nuclear Fusion.

A Star or a Sun is NOT a Planet. A Planet Does not generate its own light. A planet is a Large Rock or as in the case of some of our planets a gas giant but not large enough to start Fusion.

We see the energy it radiates towards us.

Star consumes Hydrogen but not a planet.

The Sun and stars are all a hundred times or more bigger than planets. But yes, the stars are like the Sun, some bigger some smaller.