Is this a weigela?

Yup it is.

And yes it should be that tall. I have one thats 30yrs old to my knowledge and it had been handed from garden to garden. Mine is up to the upstairs windows. Its beginning to look like a thicket! I cut it down ruthlessly every couple of years or so. I rewards me with arching branches of flowers probably 2ft long.

Does it have to be in a pot? It's not really a shrub for container growing. You should prune it after it has flowered to keep it healthy.

Thankyou for all of your replies. The reason it is in a pot is because my sister gave it to me & we thought it would be the best place until we find the best place to plant it.