Chess engine with danger (mate) warnings for beginners? I am new to the site and would appreciate help in this area.

At my current stage (beginner) I have started to draw or sometimes even beat the computer at low levels (ex. chess.com level1,2,3, lichess.org level1,2). One of these sites has an interesting feature that helps me a lot, it is a set of 3 numbers like a score. Here is an example of a game where I play White and I am behind 2 pawns (-2pts in material):

        +2.90 
        -1.78 
        -2.14 
        Stockfish.js 8 | depth=19


Which I interpret the following way: 


Positional score shows max=+2.90, which means that there is a tactic opportunity involved (overloading? removal of defender?...etc I must find out!).
If I see the opportunity and play correctly, I can materialize the advantage and win an important piece (maybe win a rook, or take the queen in exchange of one of my rooks)
If I miss the opportunity, the next score will be -1.78 (second best move) or -2.14 (third best move).
That is, the momentary positional advantage will disappear and the score will revert to the material strength (2 pawns behind).


Well, my problem is that I sometimes blunder and my score goes abruptly down to for instance -M2 [mate-in-2 for Black].
I lose the game :( because I did not realize that there was a mate danger (ex: last rank weakness or something like that).
The score of the site I am playing only shows the 3 best moves, not the WORST moves.

I am formulating this question here in the hope that someone knows other sites for beginners, with an engine that can be tuned to warn if there is a risk of blundering and being prematurely mated.
If I do not find such feature, well, I will have to be patient and continue with the learning process:). The frequency of blunders should decrease as I gain experience.

Thank you for your help.
Showing only the worst moves for a position is not something you'll find. Computer engines are not appropriate for warning against risk of blunders. My suggestions:


Take back a move against computer if you make a bad move
Review your game


You're asking the question because you're afraid of losing. There's no shame to lose against a computer. You learn more by going back your game (or takeback) then explicitly being warned.