I have a problem with my \textbf and \textit commands, it makes my texts bigger than when no styles are applied.
An example is shown here:

I also put an URL inside the bold command (\textbf{http://www.stackoverflow.com/}) and it doesn't go back to the new line, so i have to manually put a space between words...
This is basically my header:
% Packages
\documentclass[a4paper,10pt]{article}
\usepackage{graphicx}
\usepackage{array,multirow,makecell}
\usepackage{fix-cm}
\usepackage[utf8]{inputenc}
\usepackage{indentfirst}
\usepackage{amsmath}
\usepackage{eso-pic}
\usepackage{fancyhdr}
\usepackage{color}
\usepackage{hyperref}
\fontsize{12}{12}
pagenumbering{arabic}
\section{Section}
\subsection{Subsection}
\subsubsection {Origin}
\par
Lorem ipsum \textbf{sit dolor amet}

\beforepagenumbering. – Ian Thompson May 06 '14 at 20:34