Bystolic 5 mg = very bad side effects for me. How long before out of my system?

Usually 2-3 days.

I realize this answer is very late but may help someone in future.

Nebivolol is metabolized by a number of routes, including glucuronidation and hydroxylation by CYP2D6. The active isomer (d-nebivolol) has an effective half-life of about 12 hours in CYP2D6 extensive metabolizers (most people), and 19 hours in poor metabolizers and exposure to d-nebivolol is substantially increased in poor metabolizers. This has less importance than usual, however, because the metabolites, including the hydroxyl metabolite and glucuronides (the predominant circulating metabolites), contribute to β-blocking activity.

It takes 5.5 x elimination half life for a medicine to be cleared from ones system. Therefore if we use the longer half life of 19 hours then it should take approximately 105 hours (5.5 x 19 hours) for Bystolic to be cleared from ones system.

https://www.drugs.com/pro/bystolic.html