I won't claim to know what you're going through, but in my experience these are things that don't "subside". It requires a lot of work to improve mental health.
Whether it's through seeing a psychiatrist, or just managing your symptoms non-pharmacologically (i.e. daily exercise, sleep hygiene, socialization, healthy eating habits), you have to take the first step to get your symptoms under control.
If this is situational, like a death in the family or caring for someone with an illness, it makes more sense to wait for the situation to resolve. But if this is a flareup of chronic, underlying depression and anxiety, I don't think it makes as much sense anymore.
But I think you need to think about what's going to change a year from now. Do you have a plan to work on your mental health? Is that something you can't implement between now and the start of M1? Or are you just going to hope that your symptoms spontaneously resolve by next year?