Hi carlrose, how are you doing today? Sometimes I feel sad for seemingly no reason too.
God gave us our emotions, and sadness in and of itself is not sin, even though some Christians act like it is.
There is almost always an underlying reason why we are sad. Sometimes when I don't understand what I'm sad about, I pray and ask God to show me. He always does.
God can't help you with what you're sad about until you understand what it is about. He wants you to talk it over with Him. He wants to be your best friend and have an intimate relationship with you. And talking over things that make you sad, matters to your Father.
Being sad in and of itself is not sin. It depends what we do with our sadness. Look at this passage where Jesus' sorrow was so deep that He asked the Father if he could just be lifted out of the sadness.
Matthew 26:36 -39
"Then Jesus came with them to a place called Gethsemane, and He told the disciples, "Sit here while I go over there and pray." Taking along Peter and the two sons of Zebedee, He began to be sorrowful and deeply distressed.
Then He said to them, "My soul is swallowed up in sorrow--to the point of death. Remain here and stay awake with Me."
Going a little farther, He fell facedown and prayed, "My Father! If it is possible, let this cup pass from Me. Yet not as I will, but as You will."
Jesus' best friends, the disciples, weren't there for him. They said they would be, but they really weren't. Often it is like that for us, too.
But Jesus has promised that He will never leave us or forsake us:
Hebrews 13:5b-6 "for He Himself has said, 'I will never leave you or forsake you." Therefore, we may boldly say: The Lord is my helper; I will not be afraid. What can man do to me?'