Video not appearing in timeline

I am currently working on a video. For that, I have recorded a video of nearly 30 minutes (I will use some parts of that). I have done most of the work but when I drag the clip from clip area (or whatever it is called where all of your clips are present) to timeline, only the audio appears, not video. It just transfers only the audio to the timeline. I have checked the video by playing it in a video player but there appears to be no problem. It plays really well with the video. And even when I move my pointer from above the clip in the clip area, it shows the clip playing. Please don't tell me I have to record it all once again. Here's a reference picture of it (ya I didn't record the audio as it was not needed for the video I am making).

Edit: I just now noticed that it does not happen with just one video. It happens with each and every video. Even the one's who are already in the clip area don't have video in timeline when I drag them.