< It's so easy to fall into pessimism
Isn't there this old saying, that the two sides (optimist and pessimist) live in you and everyone anyhow. You can't get rid of them. BUT you can decide to feed one a bit more that the other. For example, every evening while going to sleep, try to remember at least one little thing during the day, that made you smile. Be it a thingy you accomplished, a deed you completed, a "magic moment", a nice conversation with someone else, whatever ...