I do have a question. Not only am I new to this bo

I do have a question. Not only am I new to this board, but I am also new to investing period. Every day this week and last week I have put an order in to buy some of this stock. Just increasing my holdings. Today was the first day it went thru, but only partially filled. If the price is down at the price where you are wanting to purchase the stock, why doesn't it get filled? And it's not like the price dipped and then jumped up. There were days it just sat there at the price.