Is there a word for Negative Nostalgia

I think the word you are looking for is 'flashback'. While it does not have the exact connotation, because it implies suddenness, it most closely approaches a 'negative nostalgia'. It is usually used in the plural, as in 'flashbacks'.

[A] sudden, clear memory of a past event or time, usually one that was bad.

(Cambridge Dictionary)

So to complete your example, I'd write 'this burrito is good, but I don't think I can finish it, it's making me have flashbacks of that time I ate a burrito and got food poisoning'.

The WRONG word to fit your example is Pine.

Example; once ensconced in the bank , George began to pine for the smell of a cricket ball , the sound of chalk and the companionship of his chums" ...cripes, too much Wodehouse methinks!

As @Pluto thePlanet has noted that was a duff answer. The word Rue may be worth considering; "This burrito is good, but I don't think I can finish it, it's making me rue that time I ate a burrito and got food poisoning."

There's no exact corresponding term to 'nostalgia', one that captures a vague memory of feelings in the past, but negative instead of positive.

However, there are multiple words that come close and fit well within your pattern.

The most likely one is the noun

regrets - worries over past action.

or essentially bad memories of past actions (nostalgia usually doesn't concern primarily actions, while regrets do).

But in your example sentence, the bad memory is about a past action:

"This burrito is good, but I don't think I can finish it, it's making me regret that time I ate a burrito and got food poisoning."

(used here as a verb, but could be reworded to say "... making me have regrets about that time...").

There are other synonyms that are further away: remorse, heartache, misgivings, lament, qualms. Note that 'nostalgia' is given as a synonym of 'regret', but I don't naturally associate 'nostalgia' with negative memories so I question its use for both positive and negative.

Ruminate as it is used in the psychological (vs. lay) sense seems appropriate.

Rumination means "to repetitively think about the causes, situational factors, and consequences of one's negative emotional experience".
[Psychology Today]

Example: "This burrito is good, but I don't think I can finish it, it's making me ruminate about that time I ate a burrito and got food poisoning."

If by “bad” you mean at the level of PTSD bad then the word we use is relive.

verb

1 live through (an experience or feeling, especially an unpleasant one) again in one's imagination or memory."he broke down sobbing as he relived the attack"

Oxford Languages

These are intrusive thoughts that replay, unbidden, though your mind making you feel like you’re going though it again.

Maybe 'lament,' or 'anguish'/'anguish over'

"This burrito is good, but I don't think I can finish it, it's making me anguish that time I ate a burrito and got food poisoning."

Rue.
It's usually used about a past, sorrowful event, but also less commonly used for a past event with negative consequences.

n. "I'm in rue thinking of eating another burrito--last time I had one, I got food poisoning..."
v. I am ruing the idea of eating a burrito...."