Hi Avery
I don't think it's possible to remain in line all the time. People who say they can are either lying or hiding from life. The only way to remain in line ALL the time is when it's over and you're six feet under - that ain't livin'.
Negative thoughts and feelings are nasty, but I don't think it's wise to ignore them or push them aside. They could be telling you something important. Instead, I try to explore those thoughts to see if I can figure out the source. If not, I spend that time praying/meditating for understanding and strength to endure.
We'd be off balance if we never experienced the negatives in life. If you pay attention and don't swing too low, it will give you the strength and energy to fully appreciate and participate in the positives.
I hope you're feeling better soon.