I agree it's quite difficult and sometimes even makes me exhausted taking care of my son. He's 3 years old and I'm a stay at home mom. But one thing I know for sure, he has helped me grow to be a better and stronger person. And I know that comes from my love for him.
There are so many ways to show children your love for them. It is through words and actions, but especially the latter. Because children easily remember their parents way of treating them. A simple hug, a smile on your face when they are around you, a compliment and by listening to them... Just those little things make them feel they are loved and they can grow to be individuals with good self confidence and self worth.