Yes, sepsis is a serious condition. Those with it are probably not sitting around wondering if the have it—they're ILL and most likely hospitalized.
A LOT of what you're feeling can probably be attributed to stress, and also the start of a new medication, especially that dazed feeling and nausea. It's great that you're starting medication, but remember, it's not a miracle drug, so if you perpetuate the negative reinforcement behaviors (such as googling), you're not going to find much peace. There's no way to just get over one specific health fear. Yes, you could reasonably assure yourself that you're not about to get a septic infection, but then new disease fears would no doubt take over. The best way to alleviate overall health fears is to get your stress and anxiety levels down. After weeks/months of doing this consistently, you'll find that you're less symptomatic and that (hopefully) you're reacting LESS fearfully to the symptoms that you do still have.
That's the key—a lot of us just want the symptoms or sensations to stop before we decide to stop being scared, but what really has to happen is that, despite having xyz scary symptom, you choose NOT to react fearfully. How you react really has more of an effect than anything else, because if you react calmly, you're not pumping more stress hormone into the body and you're not perpetuating the fear/symptom/fear cycle. A lot of us like to think that we "can't help" but overreact, but in reality WE CAN. It takes effort and practice, but it's totally doable. Getting over an anxiety disorder is not a passive exercise. It takes day by day, hour by hour, sometimes minute by minute mindful decision making on our part to get us there.