i will start off with points you likely dont want to hear but should and the rest:
1) your not finished your development till about age 25 in males, using aas before this time can stop and/or mess up your endocrine development and thats for life (its not like that with people over this age and why we rec not using aas at a young age) you may end up needing to take test every week for the rest of your life after this or much sooner than would have been.
2) letro is very strong and whom ever is giving you this info doesnt know what they are talking about ( i dont care if hes a massive old dude, he doesnt, its not hard to get big over years, even for those doing things recklessly and sub-optimally) letro I use as my main AI but only 0.25-0.6mg every 3 days in most settings... you are taking way too much
3) nipple and breast tenderness doesnt necessarily mean you have gyno, your playing with hormones and sensitivity can happen and might not be gyno.
4) you wont get gyno in a week of using teste...
5) you are lacking a great deal of information to do this safely and effectily even if you where 30 years old and i suggest you stop right now and save this for later on and research alot over the next few years.
6) maybe your letro is bunk, but again you only been on one week of teste and think you have gyno which is silly, no offense meant.
7) if you have gyo already from puberty i would deal witht hat before touching aas
8) whats your stats?
dont brush off this info above i urge you its very important you take this in and dont be hard headed about this, and im sure others will chime in on this with the same type of advice.