Hello OP! First of all, sorry for my wordy response since English is not my first language. Thank you for your understanding!
I was a 45%er when I had 3000 battles and I'm currently a 50%er with approximately 5500 battles. My 30-day WR is climbing steadily towards 60%, although I suffered a lot from a series of losing streaks last week ---- I got a blue WN8 on my Tiger II, with a WR of 44% over 100+ battles. And now I've managed to get through it. So hopefully my advice will help you!
1) Try to stay in your comfort zone for a while. When I realized that my skill was insufficient for tier 8 battles and above, I went back to tier 6 and started my "reroll" with VK3601H and ARL44. I learned maps and positions, practiced them in training rooms, watched replays from good players and videos about different tanks, read articles on the forum and other resources. After all the hard work and nearly 1000 battles in tier 6, I got a 65%+WR on VK3601H and a 60%+WR on ARL44. Then I started doing something different. I've ground several lines in Mad, Gravity, Reality, Burning games. It doesn't affect anyone's stats, and I can learn the pros and cons of so many vehicles (especially the ones in high tiers) while gaining new insights into the maps. As a result, I grow a lot in my comfort zone.
I've checked your stats on blitzstars. It seems that you perform better in tier 5-7 heavies. So why not go back to lower tiers and focus on playing the tanks that you are most comfortable with?
2) When getting out of your comfort zone, set goals for each tank you play. For example, when I decided to go up to tier 7 and tier 8 after I reached 60%+WR on tier 6, I set my goal on Tiger I and Tiger II (cuz they are a part of the E100 line, which is good for practicing the basics of heavies) ---- 50%+WR and a blue WN8. Focus on 1 or 2 tanks each time. Learn their characteristics. Watch videos. Platoon with friends who are good at these tanks. And when you reach your goal, switch to another tank, set goals, learn about it, hit your goal and repeat. Believe me, you will benefit a lot from it.
3) Don't play too much every day and if a losing streak happens, stop playing and get something to do in real life. After losing streaks last week, I decided that if I lose 3 battles in a row, no matter my fault or not, I should immediately quit the game, get a drink and calm myself down. Sometimes you feel difficulty controlling your mind after continuous losses, and this leads you to unwise decisions and emotional reactions, and eventually more losses. Now I only do a few battles each day and if I lose 3 battles in a row, I just quit and get a cup of coffee.
Remember as always, it's just a game. Just like what Bushka always says, Stay Happy, Stay Healthy.
Good luck and Panzer Vor!