A dream from the Lord will do a few things in every case, it will be peaceful, creating no anxiety. If you are prompted to wake up, it will typically take place between two and three in the morning. You will not experience tired side effects as a result. The dream will be instructional about something you should do, or a warning of something that is about to happen. It will always bring glory to the Lord in the end.
A dream from the enemy is the opposite, it will be hurtful to you or someone else. It will be self serving and in some cases create anxiety. There will be nothing in it that will give glory to God. It will typically create a problem for someone else in the long or short run, including you.