I took 90mg of Ritalin this morning, should I be concerned?

According to my psychiatrist I am supposed to take 30mg ER in the morning and then 20mg IR if I feel the need in the afternoon. On exam days I usually take 40-60 mg because otherwise I won't be motivated to do ANYTHING even in a "high pressure" situation like an exam. Now this was a really important exam (Abitur). I took 30mg ER after breakfast at maybe 7 am. Then 20mg IR at 8:30am, again 20mg half an hour later at 9am cause I wasn't really feeling any effects. And then eventually I took another 20mg IR at around 10-10:30 am, since I was really desperate because the exam was so incredibly boring and not engaging at all. So all in all I took 90mg of Ritalin within a 3-4 hour time span. I googled it and apparently the highest prescriped dose for an adult is supposed to be 80mg throughout the day so now I am a bit worried. Surprisingly I don't feel anxious or on edge but I'm scared that maybe alexithymia could beconcealing it or something. I don't have heart palpitations, my heart rate seems usual to me. I was just sweating a lot but that always happens when I take my meds. Will this have any long term negative effects? And why did I not react to my meds (if anyone has an idea)? And does that mean that a dopamine deficiency isn't really my problem? Because otherwise the meds should have worked