I haven't used TT much lately, but I too have been losing as well. Recently I have fallen from 1700 to 1654 with 3 straight losses. Who can say - chess players certainly have slumps just like baseball players, Renata.
Horrible losing streak
Queen of Knights, I want to say that my sympathy goes out to you. I have been in this same situation where I feel my studying is going well, but then my games become disasters. Here is one view point that I have taken recently and it has worked well for me.
Stop studying for a little while and just play games. The reason I say this is because, when I stopped studying, due to my mind feeling like mush and not able to compose a single unified strategy, it was because I've been pushing myself to hard and studying to many things.
When I stopped this studying for a period and just let myself play games, I actually did better. I've been toying with a notion that one needs to studying for a while and then just play games for awhile to allow the information taken in to transpose to the board. (I hope this makes sense.)
Essentially, I took in a lot of instruction but needed time to apply that knowledge before I could take on more information. Now please know that this is just something that has worked for me and I don't know that this is a universal theory or not, but I thought I would throw my hat in the ring to give you a hand.
Hope it helps, and good luck to you!

Well, thank you kindly for that thorough reply, FirebrandX, and for doing some research into my games, AND for the obviously excellent advice.
I'll definitely keep your words in mind for future games.

Don't feel bad. I'm currently rocking 815, and probably haven't hit bottom yet. Love the game though I do, after decades it's proved nearly impossible to play at even the lowest baseline of semi-competence. I'm desperately hoping merely to win a game sometime this year; in light of that factoid, your own losing streak is likely to prove blessedly temporary. Remember ... It can always be worse! Best of luck.

It happens. One time, my rating dropped from 1399 to 1250. I just kept fighting, and it's now 1380. Hoping to break 1400 soon, but mostly, I suppose I'll say, "Enjoy the game! Just relax, focus, and the wins will come eventually! Best wishes!"

Chess isn't 90% tactics like some people believe. You need the strategy and positional play for the tactics to come alive.
Your TT rating might be close to accurate, but if the rest of your chess skills are well below that, your actual rating will be lower.

Sometimes you're just bored of it and start making lazy moves, done that a few times recently.
And with tactics trainer I feel it rewards you too much for instinct and doesn't punish enough for wrong answers, whereas in a game a bad move is normally punished a lot more severely than taking a bit of extra time.

Losing streaks are normal, part of chess and no need to worry. My 11th video lesson covers this topic, they whys and how to get out of one. It's on my YouTube channel and somewhere in these forums, not yet added to the 10 on my website. See my profile for my site.
I've lost like, 9 games in a row these last couple of weeks, which is weird because according to tactics trainer, I'm better than ever before (broke 1600 a couple of days ago).
So why isn't this apparent new chess knowledge that I've gained reflected in any of my recent games? Is tactics trainer really that accurate in its rating assignment to most puzzles? Have I truly improved or does my losing streak clearly dictate otherwise?
We've had the TT discussion before, so what are your losing streaks? I need to wallow with someone in this misery.