Sometimes life presents certain situations that could get you down, if you choose to let it. Sometimes it's so easy just to pout, scream, cry, swear, and stay in bed a few days. However, that route isn't very satisfying. It makes you feel bad, sad, even angry. Holding onto those feelings eventually can cause physical sickness. So why not do the work & feel better? Once you learn to start thinking more positive, working on communicating why you are feeling these things, and then working on letting them go, the work becomes easier. To the point where you begin to say, "Yeah the whole staying in bed pouting thing is not an option," and you put your big girl pants on and do what needs to be done.
It's a beautiful thing actually when you can start to catch yourself in that process. You say "ah wait I'm focusing on the negative right now, and allowing that to control my mood and feelings, I don't want to feel negative, I want to feel positive." You then change your focus. It's beautiful to reach that point. Be patient with yourself because somedays the negative will be harder to kick than others, but if you can be the one to stop it, that's progress. Each time you stop it and shift your energy back to positive, the easier it becomes to remain positive and come back to positive more quickly.
When it is hard ask. The universe will help you find the positive energy and let go of the negative if you ask. Pray for it, ask for help getting the positive energy, surround yourself with positive people, plan fun things, do a sage cleanse, do some earthing etc, whatever you find that works for you. If you set your intentions of wanting to remain positive and something negative comes up, ask for the positive; it will come. I promise.
I can say this because it's been a process of mine for a while, and I have been seeing the change & feeling it. I can honestly tell you from experience that if you do the work, it will pay off.