3 years is absolutely nothing in stock market terms. Check in a decade.
Also you should really just invest in a super broad index fund instead of your specific tech and healthcare and stuff.
If you had only invested in a broad stock wide index fund, your 15k would be 17k right now. A total market index fund minimises risk nicely.
Honestly. I’ve saved every number I call, like “Doctor Clinic” and all that, and I only respond to calls from unknown numbers if I’m expecting a call.