Would God be angry with the questioner for not completing seven rak'ahs of the qiyam al-layl prayer as she had vowed, due to obsessive-compulsive disorder?

Satan takes control of a person afflicted with waswas (obsessive whispering) to deter them from good deeds. Such a person must strive against their self by ignoring the waswas and not paying attention to it, along with supplication and diligence. There is no sin upon one who neglects Qiyam al-Layl (night prayer) unless they made a vow concerning it. Saying "I will pray such-and-such every night" is not a vow, and a vow is not established by doubt. Persevering in Qiyam is more virtuous and carries a greater reward. If illness prevents a servant from performing Qiyam, Allah will record for them the reward of what they used to do when healthy and present.