There's a load of articles and studies online that suggest Facebook is bad for those with low self-esteem. If anyone feels bad about themselves, then Facebook's just gonna amplify those feelings, making them feel worse.

I have felt worse from using it, but not because of self-esteem, but because I'd waste so much time on there. I could've spent that time bettering myself or working towards my goals.

You've got to ask yourself whether or not it's worth it to go on Facebook. Does it overall make you feel better or worse? If it's the latter, maybe deactivate it temporarily, so that you can take a break from the negative effects it's having on you.

Facebook makes us focus on other people's highlight reels, so getting away from that for some time might help you focus on more positive things instead. This could help a lot with confidence.

Good luck. And please please try to not be so hard on yourself. The negative voices in your head are telling you lies. You're not ugly or inadequate.