First, there is no proven link between serotonin and depression. What is known is that altering how your body utilizes serotonin can make an anxious or depressed person feel less so, but that doesn't do anything to cure the disorder. So no, nobody "has" to take an ssri to combat depression, and many antidepressants don't target serotonin or target it exclusively. Second, normal is a relative term. We're all individuals, and while we have much in common, we also have much that is unique to us. Being down isn't depression, it's feeling down. Depression is when you feel down chronically for no apparent reason to the point where life becomes unpleasant and hard to live. The only known cure for depression is talk therapy. Different psychologists use different methods, but that is the only method known so far to cure depression. Because therapy doesn't work for everyone, medication comes in when life is just not going anywhere. It can help you live a more pleasant life and also stop you from sinking further and further into your funk. If life becomes that bad, medication is there, and can help. It does have significant downsides, as does all invasive forms of medicine, but at some point when life isn't liveable anymore you have to try something. There's also the field of natural medicine, which is harder to do than just taking a pill. It requires a commitment to a holistic program of supplements, therapy, lifestyle changes, dietary changes, etc. with a lot of experimentation. Some people find relief in religion. Many people just get better as mysteriously as they got sick. Try whatever you think will help, and if it doesn't, don't worry that you might have to be on an antidepressant -- you wouldn't feel that way if you had any other illness that nothing fixed and only medication controlled. But bottom line, yeah, lots of people get over depression without medication. There are other ways.
It depends what works for you.
After trying MANY different antidepressant medications, none of which worked, we FINALLY found one that actually worked wonderfully.
Now I'm fine, and I never think about it. We tried stopping my medication and I went downhill. We tried other antidepressant medications, none worked. Eventually I begged my doctor to put me back on the medication that worked, and I slowly got better again.
We repeated that experiment 3 times over the next many years. (We weren't very smart back then.) Every time the same result. On the medication I'm fine and normal and don't think about it. Off the medication my life slides downhill into hell and it's all I can think about.
So for me it's going to be medication for life, and no problem because it works great.
I've asked my psychiatrist this question, do other people have to take it for life. My psychiatrist said well some people if they've been taking it for a year, then they can try going off the medication and see what happens. It depends on the patient. Some do fine without the medication. Others slide downhill and need to go back on it. It's an individual thing.
My psychiatrist did say they like to wait a year before going off a medication that's helping. The longer one stays on the medication, the more likely it will be they can successfully go off the medication. A year seems to be the time frame doctors settled on as the minimum amount of time one should stay stabilized on a medication before trying to go off it.
I used to think medication was a horrible stupid idea. Sounded totally artificial, like covering up a problem with pills. Instead I discovered when I found the right one for me, it fixed whatever was the underlying problem, and allowed me to recover and feel 'normal' for the first time ever. I was astounded, as I had never felt 'normal' before. I just assumed everyone suffered like me but was good at never mentioning it.
A lot of people do stay on antidepressants long term throughout there lives. There is a belief that the more episodes you have, the more chronic in nature the condition is and that treating it without interruption makes sense. No shame in that in my opinion. The goal is to have a functioning and full life. So so so many people do that up and down thing of starting their med because things are bad, deciding it wasn't necessary and then taking themselves off of it and then getting depressed again and going back on the med and it continues. That's really probably not the best way to handle it. But also, just taking medication isn't the best way either. All the OTHER things are very helpful in feeling better. Therapy to learn coping skills, life style changes, exercise, etc. all are of benefit. Let us know how you are doing, we're here to talk you through it!