It sounds like an anxiety or other emotional reaction. You say "some content," do you mean porn? Given it's only been a couple of days, I'm guessing it will go away unless you do have a more chronic anxiety problem that leaves you obsessing over things often. If it's just the one thing and the one time, give it some time, it'll go away. A lot of people feel emotions in their stomachs. Very common.
Is it from arousal? I agree that it is likely anxiety as it does not sound like it is in your testicles which could be epididymal hypertension (blue balls) https://www.medicalnewstoday.com/articles/324870 Have you ever dated anyone before?