I can't enter a game of minecraft with a friend. Launcher isn't working right.

Hello, I have been trying to play Minecraft with my friend for a long time. maybe a couple months, I got Minecraft almost a whole year ago and just a few months ago I had this problem with the launcher that wouldn’t let me play Minecraft with friends, rarely lets me get on once when the launcher isn't acting up. Can someone recommend something to me or help me out perchance. I got on yesterday but after i closed out the game the launcher was acting up and I spent 3 hours trying to get back on. didn’t work again.