I try to grasp and acknowledge the feeling, that I'm feeling sad, so then it'll be easier to accept that I'm not feeling okay, and I always remind myself that it's not a shame to feel sadness. It's normal, people go through the same thing so I'm not the only one going through it alone. It's also important to note that when you feel sad don't try to make yourself feel the opposite, don't tell yourself that you can't be sad because it'll be harder to get over with. What you want to do instead is embrace the fact and just let it be until it doesn't feel saddening anymore and then you can go as the day goes. Just remember not to dwell. We all have such a limited time in this world, why not use it to create our own happiness worth celebrating and reminiscing?