I've been using phenylephrine 0.5% for nasal congestion for more than 5 years daily, is that bad?

Yes, it is bad. Topical decongestant sprays are usually safe when used as directed.
However if the spray is used more often than recommended, and for longer, the sinuses begin to require more medication to achieve the same effect, and this persistent overuse can actually exacerbate congestion. This condition is called rebound congestion.
If you continue to misuse the nasal spray it can result in permanent damage to the nasal passages. Termed "rhinitis medicamentosa," this condition comes with sinus dryness, persistent stuffiness, regular nose bleeds, headaches and even a loss of smell and taste. Some addicted patients also complain of feeling jittery, irritable and thirsty, especially as their medication dose wears off.

You should see your doctor as soon as you can to work out a plan to treat your rhinitis medicamentosa.