After the session the DM pulled me aside and reminded me two other members of the party have also died, and are still with us.

Sounds like you're probably fine then. Or approximately fine, at least - last time I did that to a player I meant the party had enough funds for a reincarnation ritual, so apart from turning from a halfling to a gnoll the biggest consequence was the other PCs having to explain to the dead PC's parents that their daughter had been eaten by a Froghemoth.

I was gonna say, at 11th level your party should be able to scrape together 5,000 gold for a Ressurection, or even possibly 10,000 for a True Res. Hopefully you're back in action next session.

One of my Wizards died at level 3, then again at the perfect moment at level 16, then after level 20 she started dying almost every single fight we got in that she didn't get the initiative, until we hit level 28. Then she became functionally invincible.

The level 16 death was perfect, because she had already paid for a True Res, and so she was ressurected perfectly, almost instantly. Thing was that was where the session ended, after I confirmed that I was, in fact, alive, the DM handed out XP. He didn't intend to do it, but he accidentally gave me 100XP more than I needed to level up. We also had access to a plane that we called "The plane of Time," which basically gave us an instant long rest anytime we needed it, until we broke the plane later in the campaign. so from the perspective of the bad guy, he kills me, me and my entire team just vanish for about 12 seconds, and then I'm back and suddenly throwing 9th level spells at him. Specifically he died because of my character's Signature Spell. Unfailing Missiles. Dude took 196 points of Force/Sonic damage to the face, and died. That was the one time we didn't collect the Epic Magic Items, and Artifacts the dude was wearing, since his God (God of War) showed up at that point, killed everyone on the dude's side, and told us to "leave with your lives and what you came with and nothing else." 15 minutes later he magically nuked that city off the face of the world. Even The Wizard's College that I worked for was a bit unnerved that killing me just seemed to make me stronger.

If you were inclined to seek a change, I'm sure your DM would allow you to roll a new character. But revivify is a thing, and sounds like your DM is more concerned about your fun than sticking to punishing consequences. Either way, hope you continue to have fun!