Maybe a Stockfish Bug? Is this position a draw?

Hello, after playing a game, in a position I thought it was a draw, I started the stockfish to confirm if it was or not a draw.
For my surprise, it was not a draw, however, the stockfish points are really volatile, and I don't understand anything; and finally, I could not figure out if it was or not a draw

From here:
After the blunder 35 ... Rxb5 I knew than I was not lost anymore, and at least, I could draw the game; however, Stockfish is saying +4.7:
http://es.lichess.org/j4Ca5evA/white#71

Black played 36 ... g5 (stockfish recomendation using arrows, and its not a blunder or anything; however, I thought about playing Kd7 for example, and in fact, Stockfish now detect 1.8) How is posible than Stockfish recommend g5 with g5 with 3.8 and ignore Kd7 with 1.8?

After this movement, http://es.lichess.org/j4Ca5evA/white#73 here happens aproximatly the same;
Stockfish recommend me 37. fxg5 with +0.7 punctuation; I played g3 with +4.8 (How is it posible than Stockfish recommends you +0.7 instead of +4.8?)

After all, I won (I knew I had a better king position and if I could arrive to c6, moving around d7 I would win; indeed, I achieved the d7 square and I won the game) but checking the crazy of stockfish I can't know if I did my best or not, or if this situation was draw or not; Stockfish is not helping me at all. Some expert players can help me?

Thanks

Here, http://es.lichess.org/j4Ca5evA/white#72 the arrows recomend me

I didnt totally understand your post and question, but my houdini is saying after 36. Kxb5 its totally winning with any black move. The post game analysis is rather shallow so perhaps the comp is fluctuating due to lack of depth to see the win, but its clearly completely winning. +5 for white and he has a forced promotion sequence. For example 35...Kd7 is rated -5.23 while 35...g5 is rated -5.24...black can only pick his route of losing here

You could download stockfish yourself to analysis, its opensource\free and going to be much deeper on your own PC when you let it think for awhile.

I was talking about Lichess Stockfish, or lichess feature to analyse your own games.

But okey, I understood your point, thank you.