Some great advice from happy helper and hassan - especially the phone rule (social media is never a good idea to delve into when you just wake up!)
I personally can find myself feeling sad about whatever it may be - and when I do, mindfulness can really help me stay grounded (e.g. meditation, tarot, deep breathing) etc. and be fully present. That is important.
Going for a walk in nature or around to move your body is also calming and helpful to stay present - along with driving is very therapeutic for me.
Seeing a psychologist or your GP is also important in managing these feelings if you feel like it.