In principle, you have to continue to go to work. Nevertheless, your employer has the duty to have regard for the welfare of employees under labor law. This means your employer must do everything in their power to ensure you remain healthy. For example, employers must allow remote work whenever possible. If not, then employers must ensure that safe distances are maintained or a so-called “medical mask” is used. Surgical masks and FFP2 masks are considered “medical masks”. Your employer must provide sufficient medical masks.
Talk to your superior and inquire about feasible health-related measures. Sometimes, measures such as remote work are regulated in company or works agreements.
If your employer ignores employees' safety and well-being, speak to the works council in your company or inform your local Health Office (“Gesundheitsamt”) . You can find your local Health Office via Behördenwegweiser.