Wait, don't worry!
Getting a lower test score on a practice test isn't necessarily a sign that you aren't improving or that you're getting worse. This back to your earlier tests... were you more accurate, or were you a lucky guesser? This may not be true in every case, but it happens a lot!
If that doesn't sound like you, then something else is happening. Like the situation below.
Learning takes time
There is a learning curve to new material (not just test material). This means that at first, once you have started using a new approach or applying new information, your speed decreases and your accuracy tends to dip, too. Have you ever had to completely organize a room, so first you had to take everything out of drawers, boxes, etc.? It looks like a disaster (worse than before you started!) for a while until you finally start to see improvement. The same thing happens when studying—there is a period where new information and strategy significantly slows the test taker's thinking and can even reduce accuracy. You have to push through this and get to the improvement side.
You may be passing through the period where your mind is bogged down with new strategies and tips; you have to think very hard through each step and you have not internalized and mastered the additional strategies (yet)! You'll be okay, though. We promise. :)
Our practice tests are pretty accurate, yes, but it's actually very common for students to drop a bit in score at some point in their studies. This might because they're focusing on new, maybe less comfortable things, or just because they had a bad day. But as you keep practicing, anything new you've learned (test strategy, math skills, verbal techniques) will become more comfortable and your score will improve. The trick is to keep doing test-like, timed practice. If you are anywhere near the date of your test (less than a month), then from now on, try to make every bit of practice as test-like as possible).