University dropout is often preceded by a phase of doubt whether to continue studying, either in general or just the given subject. Mental health problems might be interrelated with this phase of doubt. Counselling services at German universities could provide help, but do not seem to reach students in need. To explore the phase of doubt and possible (inter-)relationships with mental wellbeing among university students in Germany as well as their consultation-seeking behaviour, a qualitative interview study was conducted (2017–2018). Participants were students casting doubts on their studies (n = 14) and counsellors (n = 16) working with this target group. Examples of reasons for doubts were insufficient information, unfulfilled expectations concerning the subject, subjectively poor study conditions, performance problems, and lacking future perspectives. Mental health problems were subjectively intertwined with doubts, considered as both cause and effect. Counselling services were evaluated as hardly helpful by students and as being in need of improvement by counsellors. Suggestions as how to improve such services comprise a more specific and proactive way to approach students. By considering the phase of doubt before dropout, German universities can improve their support services to be more responsive to students and, thus, prevent dropout and mental health problems.