How long you tough out the side effects?!

I just finished my first week on the generic Vyvanse (only 20mg and supposed to increase weekly until I hit 40mg). I've never taken medication of any sort (beyond Advil and etc.) before so I'm having a hard time deciphering whether I have to toughen out the side effects or if Vyvanse isn't for me.

I'm lowkey a lightweight and easily affected (like cold and flu medicine makes me feel a little high) so that might be a factor. But my first day on the meds was amazing (probably the high many people allude to), I felt so calm and mentally clear for the first time in my life.

The dry mouth helped me stay on top of water. But the past few days, I've had a building, constant uneasiness (sometimes feels like anxiety). I just feel off. I haven't been great with my food and water which I know is so important with the appetite suppression. And I have had some insomnia so my sleep has been really poor.

But right now it's 9pm, I took my pills at 7:30am. And my heart is racing and I feel awful. I also have experienced a lot of nausea when the meds wear off. And I have felt like I'm almost talking with a retainer in, slurring my words a bit which Google tells me isn't good 😅

I'm feeling super discouraged because the first day or two felt life changing. But today, the anxiousness almost made the lessened ADHD aspects not worth it.

Does it take a while for your body to adjust or are these signs maybe this specific medication isn't for me?

Thanks for your help