Is it ok to stop breastfeeding your newborn? If so then why do I feel like such a horrible person?

I stopped trying to breastfeed when my daughter was 1 1/2 weeks old. It wasn't working for us for many reasons...my milk wasn't as plentiful as she would have liked and my 2 year old son always acting up when I tried to feed her knowing I wasn't as fast to get up and put him in time out were two of the main reasons. She would get frusterated at the lack of milk at first and then she just stopped trying after a few days. I feel like I am a horrible mom for not trying longer but the truth is it was making life hard for us both and I was a weepy mess. I love her so much and wanted to give her all the best. I wanted to be the type of Mom who breastfed their child until the child weaned (like 2 or 3)..... Now I feel like she was cheated. What is your opinion on this?