hello justin82,
first of all, hair loss is just a natural phenomenon like ageing, many in the world are experiencing this even once upon a time i was. don't go into depression because todays medical science has beautiful solutions to the hair loss and moreover depression, anxiety and stress is one of the major reasons of hair loss.
coming back to your question. actually you have not posted your photographs so its vey difficult to know your grade of hair loss. but by whatever description you have given i think its a androgenetic alopecia and for that minoxidil and finesteride are the only FDA approved medicines available, you mentioned about the side effects of finasteride but i would like to ask you whether you experienced those side effects or you read about them somewhere and stop taking finasteride , because in my 30 years of practice as dermatologists and trichologists i have not seen a single patient of side effects of finesteride and even research says finasteride has negligible side effect that is 1 in 1000000 patients experience it.
i would suggest to go for minoxidil and finasteride after visiting a good dermatologists you can also try some allied non invasive treatments like PRP, mesotherapy , LLLLT, LASER COMB which will also help you stop further hair loss.
as you are experiencing hair loss for just 4 months you are seeking help at right time and it can be controlled with conservative methods no need to go for hair transplant ( try all conservative methods for 2 years atleast before going for hair transplant).
and please don't go into depression, cause depression itself is way more serious condition than hair loss. life is more than looks and hairs , and we have solution for both. thank you!