Antidepressants don't have to be for 'life' no OP, you simply reduce the dose and come off if you want to do so. Medication is a trial and error thing and AD's suit everyone differently, they also take a while to work but can be life changing for those struggling- on the other side of the coin they don't work for everyone and as I said, it is sometimes a long process settling onthe right medication and dose for you, it may not be the one type GP starts you on, say.
A couple of months 2-3 times a year is half the year OP, and half your life. I think managing your expectations that depression is potentially impossible to shift entirely is not the same as not trying any treatment for it and suffering for quote a large amount of time.
'Overcoming' it and then falling back into it I think is a potentially unhelpful way of looking at it to an extent; there is no failure on your part when you feel depressed again, it is an illness and is cyclical- whilst there are lifestyle changes that can help a period of depression occurring, illness isn't really in our control or beaten by trying hard. We can try hard and stay functional if we want but there are limits to what effort can 'cure'.
I would speak with a GP, self refer for some counselling perhaps or CBT, medication works best alongside talking therapies and therapy in and of itself is very helpful for some people.
Whilst it sounds trite, if you're used to self management I would look at, and read up on lifestyle changes that are known to help- exercise is a big one, diet can be helpful, SAD lamps if it is worse during the winter, natural supplementation (do not mix this with prescribed medicine), mindfulness and relaxation apps, good sleep hygiene, activities such as drawing and painting. None are cures obviously but if you can give yourself an advantage in managing mood then why not.