Nope, the answer is not in more medical testing. Blood tests that were fine five weeks ago will not show signs of anything sinister now. Cancer, unless it's some kind of blood cancer, does not develop that quickly.
By and large, medical testing, google searches, and other forms of reassurance-seeking fail to quell anxiety over the long-term. They might feel good in the moment, but ultimately they contribute to an overall increase in anxiety. They're what's known as "negative reinforcement behaviors" and they create a cycle that's difficult to break because as anxiety sufferers, we begin to think that we NEED those things to "feel better." Every time we feel a physical manifestation of anxiety (that twinge of pain; this palpitation), we think we need go online or call a doctor. That's what "feels right" in the moment, but the truth is, your anxiety will not be brought under control until you get to a point where you can REFRAIN from indulging any of those things. After all, fear that has nothing to latch onto doesn't stick around very long.
Do you have access to any kind of anxiety treatment? Is that something you're willing to explore?