I agree with the others that this is normal - sorry! My 19 month old still does this (and TBH it's often more than every 2-3hrs). I think some children just don't sleep that well and have that need for extra reassurance.
I agree with Snacks, that accepting it makes it a bit easier. If you are constantly thinking something is wrong and trying to change them, you feel upset and frustrated and like it's something you are doing wrong. Once you accept this is perhaps just how your little person is, it can be easier. And hopefully it helps a little to know you aren't alone!
It is very tiring, so you have my sympathy.