Does depression last forever?

Right. But why wait?: So good that you understand that "grieving" (which can be for more reasons than a death) is not necessarily clinical depression! but, that being said - if you can find a pro that you like to talk about it with, they may help sort it out better, faster and with support when you have doubts. I expect you don't need meds - if you do, it should only be very short-term. You're doing well, good luck!

Therapy can help: Sometimes symptoms of depression can last for a long time; it is referred to as chronic when it persists for at least 2 years. The good news is that treatment (medication/therapy) increases chances of getting better and staying better. In addition to therapy, individuals with depression often find The Mindful Way Workbook by Teasdale, Williams, Segal, and Kabat-Zinn helpful. Best to you