Yeah, I understand the feeling. For me, my blitz problems tend to stem from my opponents playing passive lines that I know are inferior, but I spend so much time trying to punish the lines in the most efficient way, that I end up running panic mode with the clock.
Chess Thinking Process
I tend to have the opposite, thinking and wanting to move my pieces too fast! But I try to slow it down nowadays .
I can advice you two things: play more speed chess, it will give you the intuition to see and move faster.
Two: if two moves are minimally different (which I doubt btw) then either move is fine. You should not concern yourself with the minimal differences because chess games between amateurs tend to go be won or lost by bigger blunder(s) by one or both sides. Also if you have a piece move or a pawn move that both are minimally changing the position, then always go for the piece move. Pawns can never go back!
If you have trouble analysing the position fast I would suggest study the middlegame and tactics more. Because in endgame often times one or the other side is already winning so you need to get your advantage in the opening or middlegame.

Thanks for your advice!
I do find speed chess quite enjoyable, and I take it as a concept of relaxation rather than playing chess seriously. I suppose there is a point though – that by playing quick games improve one's experience in handling and recognizing opening positions, ideas and traps.
This might lead to more time to think in the middlegame, which I guess the only solution is to study more positions and play more chess!
In both online and OTB chess games, I feel that I am not using my time to think in an efficient way.
I have played chess for quite a long time, and have some experience with playing in OTB tournaments. Often I would be behind my opponent on time – for example, in a 1 hour game after 20 moves, I would have about 30 minutes left, while my opponent would usually have a solid 45 minutes. Of course, half an hour is still a lot of time, but I tend to play slowly, and sometimes would find myself in a difficult endgame with 10 minutes to spare.
My problem with time management is the same in online games, where I play at a faster time control, mostly 5 minute games. I would find myself on low time, and sometimes leading to timeouts or making a blunder in an equal endgame.
I think my problem with time management lies in my thinking process and strategy in a chess game. Although I have read several books and articles on the opening, I tend to be very cautious still, pondering sometimes for minutes over two or three moves. I would analyze the moves for some time, and decide upon which is best. I'm not sure if that's the best strategy, especially in the opening. The difference between those moves is probably at a minimum, but I prefer comfortable openings where I have an easy position to play with, hence spending my time to decide the best or most effective move. In games with a long time control, I'd like to think of myself as a more positional player rather than a tactical player.
Should I try to play quicker and focus on the middle game or endgame more? Of course, the downside of that is, I might not have a position in which I would be comfortable with, which might result in me thinking more in the middle game.
An alternative is cutting my thinking time off of particular moves. I tend to think for quite some time when deciding over taking a piece with a knight or a pawn (or something similar). In most cases, taking with either makes minimal difference, but I would think at the position in detail.
I'm asking for suggestions as to whether to change my thinking process in a chess game, and if so, how. Feel free to also include any resources to this topic, or if you're willing, maybe share your own approach to chess.
Thanks for reading this hefty forum message.