Despite what other commenters are saying, if you ask for advice from internet strangers, I think it's reasonable to receive advice from internet strangers, and not simply get told to "go somewhere else."
So here's my internet stranger recommendation.
First, Cognitive Behavioral Therapy is the "gold-standard" (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5797481/) in the therapy route.
> "(1) CBT is the most researched form of psychotherapy. (2) No other form of psychotherapy has been shown to be systematically superior to CBT; if there are systematic differences between psychotherapies, they typically favor CBT. (3) Moreover, the CBT theoretical models/mechanisms of change have been the most researched and are in line with the current mainstream paradigms of human mind and behavior (e.g., information processing)."
But often when people go to see a "therapist", either they don't do CBT, or the patient or therapist does not realize that all the worksheets and exercises really actually need to be done. CBT is a lot like physical therapy, if you don't do the exercises, you likely won't get better. If you have not tried CBT before, or are not sure, the book "Feeling Good" is the thing to pick up.
Second, to answer your specific question on SSRIs: SSRIs do have side effects. They're not that bad. I was on them for some 6 years. However, I would rather have not have had the side effects, and not taken the drug, in part because SSRIs also didn't make me in particular feel any better. That said, on average, SSRIs do work while you're taking them for most people. SSRIs + CBT at the same time tends to be the most effective combo.
Finally, here's my non-scientific advice from an internet stranger who has been where you are, and is no longer there. Take it as you will.
In your head there's a little voice. It's the one reading this right now! You can make it talk if you want. Here, make it say "purple octopus fiddly pop". See? That's not you. You're the thing _hearing_ that voice.
That voice talks all the time.
When you roll over at night, maybe it says "oh god, maybe I'm going to get fired". Maybe says "oh, I bet I deserve to get fired". Maybe it says "oh gosh, I can't even get this depression under control, and if I don't, everything is gonna collapse". You aren't that voice!
Sometimes it plays a little movie, like the last time an embarrassing moment happened, or what you could have said as a witty come back. When the movie plays, you're not really there, but your body doesn't know that, and so it builds up all physical sensations of emotion.
That voice is a reflex in your head. When someone taps your knee, and your leg kicks into the air, it wasn't you that kicked. It's just a reflex.
Here, I'll prove it to you. Set a timer for 3 minutes and try and not think about anything. Just pick a point on the wall, or maybe watch your breath. I'll bet you can't do it. The moment you try, there's the voice again. Maybe it's saying things like "oh why I am doing this" or "this is boring". It doesn't need to be articulating words; sometimes it's just a feeling. When you wake up every morning, "with a pit in my stomach that I carry around all day", that's the voice.
Most of the time, when that voice talks, it's wrong. It might say "oh, I'll bet so-and-so hates you". But did you check? Did you ask so-and-so directly? Out loud? Did they tell you to your face?
Or did you implicitly believe the voice?
The way out of the trap that you're in is to notice when the voice is happening. It's happening _all the time_. It's probably made a comment while you were reading this. Did you realize? If, when the voice happens, you immediately assume it's correct, and act as if it's true, you train the voice to say more things.
It's gotten into such a habit that you don't even realize it's happening. It's like biting your nails; your hand moves before you even realize.
CBT is one way of breaking the habit. The most common CBT exercise ("the 3 column technique" or sometimes "catch it, check it, change it") has you write down when that automatic thought or feeling happens. And by doing this, you train your brain to catch the thought before it leads you down a spiral.
Importantly, by writing down the thoughts, you hold the voice in your head accountable. When it says "some terrible thing is going to happen tomorrow", you get to see that, actually, the voice in your head has no idea what is going to happen.
Another way is meditation. Meditation is not a calming exercise. It's a way to practice watching your voice for a period of time. Over time, you build the muscle and train your brain out of the habit of constantly blending with the voice every time it has some demand.