A phone will not help if one hit to your head finishes you off. Or, if you are busy defending yourself, how can you access the phone?

Maybe you can take some martial arts classes to strengthen your balance and give you some skills.

Krav Maga is designed for close in conflicts.

Learning some hand and arm grips/holds would be worthwhile. My brother taught my daughter some hand grips and holds that she can use for protection. The right grip and disable and almost paralyze and attacker.

It may help you deal with the anxiety, too.