I'm taking 150 mg of buproprion XL and* vyvanse (lisdexamfetamine) 50 mg (orange and white). After 2 weeks I'm now experiencing small anxiety episodes, would 5-htp help?

Try Non-drug Tx. Already your meds are risky in combination - 5-THP will not increase that risk but it is not esp known for mild anxiety. I urge you to find non-drug strategies. CBT psychotherapy, meditation, yoga - even a gym trainer may help. You can learn self-help techniques that will last a lifetime in CBT. Best!