Why do i feel depressed all of a sudden out of no where?

This is a good question, and I can't say I have an answer, but In my personal experience I've realized that this usually happens when I don't get enough sleep and am tired, or if I haven't been physically active lately, try getting outside, getting some exercise or just moving a little bit, maybe go out shopping or something, but that's just me, however there's been many studies showing exercise is a great mood booster

Because you're a human! It's that easy. Try to embrace your emotions and understand them better. Writing your thoughts on a piece of paper of sharing them with a friend (or here, on chat) can really help.

Thats a GOOD question! You should sit down and really just ask yourself why is that. It probably is a reason but you haven't paid much attention to it. Try reevaluating your life and see if you can figure it out. If not maybe see a professional to make sure there isn't nothing wrong inside

Sadness creeps up on us, weather it is a combination of a bunch of small things or a past big thing, our emotions are bigger than us and our minds react accordingly.

You may have been triggered. Sometimes it could have been something that you saw or heard. It isn't your fault. It could have been environmental

Sometimes something could be happening in your life that you don't realize is bothering you. Once you recognize what is bothering you by spending some time thinking, you can try to do whatever you can to make yourself feel better.

You feel depressed? What has been on your mind lately, and making you feel the way you do such as depressed?

Something to feel depressed because things coming to our mind. Because we ceased of the reminders of other things or we hear things that make us remember unpleasant moments

Losing hope or experiencing a death/trauma. When things are not going as planned and one gets frusterated

it might be a memory that suddenly pops up into your recollection awareness. it is not your fault. it might have been something that has been bothering you in the past but you didn't have the time or the intention to investigate it at the time. it can be helpful to look at it carefully with kindness and forgiveness.