Somebody?? Help!

Two things come to mind:

1. What is the variety? Have you grown it before, achieving very large sizes, ten inches and up? (If so, skip to the second part.) If you haven't grown this variety before, it is worth mentioning that many generalist garden plant suppliers use 'dinnerplate' to refer to anything above three inches in bloom size. It is fully possible that this is the average bloom size for this variety. If you share the name with us, someone can look up the official ADS size of that variety for you.

2. Whether or not this variety is a large/ giant, there are several things you can do to help it out. The plant looks too close to the building, and it looks like it's shaded for at least half the day from the sun...To help it reach its full potential, I'd move it to a better location. (I've been moving plants that size recently, and if done on a cloudy day/evening and watered in well, they do just fine) It's possible the plant needs more water and fertilizer, but I don't know your water and feeding schedule. Pinching the side buds will also help show the true potential of the variety, as the plant can focus more energy developing the remaining buds. Deadheading fading blooms will keep the plant actively producing more buds, and improve the look of your plant.

Hope this helps... Don't forget to stake it VERY SOON. Otherwise, the plant may well topple over with a bit more growth and blooms, or even at its current growth with a heavy rain and wind.