Then he went home, and the crowd gathered again, so that they could not even eat. And when his family heard it, they went out to seize him, for they were saying, “He is out of his mind.”
Jesus was not even understood by His own family. The press of ministry became so great for Jesus and His disciples that He had to institute protective measures. In Mark 3:9 He instructed His disciples to procure a boat for Him so He can use it as a safe platform from which to teach. I think it also served as a quick getaway transport to "lose" the crowd when it got to be too much. Jesus has to clear time to get alone to pray and can only find time to do this by rising very early in the morning to avoid the press of the crowd each day (Mark 1:35). The reports of His miracles are so sensational that Jesus' reputation proceeds Him so that He cannot enter any large town anymore without causing a stir (Mark 1:45). He keeps primarily to the countryside, evidently camping out with His disciples, but even there the crowds still track Him down..
Mark's gospel is quick to pick up on the sensation Jesus has made among the people. Crowds always surrround Him, so much so that Jesus cannot even have a simple meal with His own mother and brothers. His family thinks it has all gone way too far. They don't see His mission or the ministry, just a mess, and their response is to try to rescue Him by intervention from what they see as craziness.
Even though Jesus is so massively followed, Mark points out the negative assessment of Jesus' family ("He is out of His mind") as well as the criticism of the Jerusalem scribes ("He is possessed by Satan"). Yet neither the outrageous demands of ministry to the crowds nor the outlandish accusations of the scribes or even of His own family will keep Jesus from His mission. He saw among the crowd and His disciples people who were clearly understanding Him and seeking the will of the Father Who sent His Son (Mark 3:34-35). And that was why Jesus came: to make family out of those who accept Him and then do the will of God.