Hi all! I'm new here and I'm trying to travel in this beautiful expirience called lucid dreaming!

So, here's my problem.
I'm triyng to lucid dream 1 week now. The wild method didn't work for me so I started practicing in reality checks, so I could go lucid with the MILD one. My problem is that even if I manage do reality checks IN my dreams, I still can't go lucid. Last night i had a dream under the sea breathing normally. Not only I didn't go lucid , in fact I tried to hold my nose and mouth closed underwater to see if i was able to breath and discover if this reallity check was fine for me , but still didn't realised I was dreaming, and of course didn't go lucid. So I ended up fighting with a huge shark. Has anyone from you guys have a solution to my problem? I would be very gratefull!