Just because you aren't given the credit and haven't been recognised for your work doesn't mean you have to give up or stop. You don't always need credit, other people do not always have to know what you are capable of doing as long as you do.
If you would like to help change your mind from negative thoughts to positive start your day by being thankful for 10 things no matter how big or small watch your mood change. Also repeat before you go to sleep at night.
The saddest part in life is saying Goodbye to someone you wish to spend your lifetime with. The saddest part in a life would be to spend a lifetime with someone who didn't really want to spend theirs with yours.
Sometimes the "I would love to: see that person, do that course, get that body I really want, spend time by the ocean or out in nature, travel to that picture postcard place etc" . Becomes a distant memory. How sad is that? How sad it is to substitute