All videos zoomed in

I am not a video editor. I have very little experience in this besides putting clips together and adding the most basic of effects. I have a problem where I started a new project and the first video I put in was in a "profile" type view. Now, every video I put in is automatically put in that profile type setting so when I put a video in my sequence that is "wide screen" it zooms into a profile mode and cuts off the video on the left and right sides. The closest thing I can figure out is that the sequence settings are wrong but I have no idea how to fix that. I have started a new sequence based on a clip that is widescreen in hopes of fixing it but now all videos, widescreen or not, are too zoomed in. I made a video last year with this program and did not have this problem. I really don't want to start over but no tutorials or faqs are helping me at all. The only thing I've been able to do is zoom in or out of each individual video. This is not sustainable as I have hundreds of videos to go through, some through phone, some through GoPro. I can't just go through each clip and adjust accordingly. I just need it to adjust at least to the GoPro video's size but even those are zoomed in when I create a new sequence with those. What are the right settings? Is there another way around this that I'm missing because I'm a newbie?