Is there a word for Negative Nostalgia
Nostalgia is generally positive memories (sometimes through rose colored glasses) of past events. Is there a word for the surfacing of negative/unhappy feelings/memories?
So for example, one might say "This burrito is good, but I don't think I can finish it, it's making me ______ of/for that time I ate a burrito and got food poisoning."
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'.
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.