You’re fine. That is to be expected. If you are sticking with 10x3, then:
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you are still within CW’s recommended hypertrophy range of 24-50 reps per bodypart.
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you should stick with this weight until you can “comfortably” handle 10x3. Even at that point, the legendary Vince Gironda used to advocate using this same weight for another 3 workouts or so to really “milk” all the benefits from this weight/rep scheme. You will not, and in my opinion should not, be able to add reps every workout. Progressive overload does NOT have to take place at every new workout when you are still using a weight/rep scenario that still stimulates.
Once you get back to 10x3 then stick with it for 2-3 more times and then jump the weight just slightly. If you can picture a helix, then you can get a good picture of how training works overall. Each time you complete a rotation on your way “up” a helix (or spiral staircase) then you are at the same position horizontally that you were at many other times, but you will be at a higher vertical point. Your training progress will be much the same.
Some element will be the same, but one or more other element(s) will be on the rise (either volume, load, or density). But this is not a perfect process so you can hover a while and still gain the benefits of a particular weight before upping one of the three variables of progression listed above. This progression is to be an OVERALL TREND.
In fact, I sometimes like to stay with a weight for about 3 workouts as Vince suggested so that I gain a level of confidence and comfort with it, before I move up. And take note, if the workout is getting easier now that you’ve made 10x3, then you are STILL progressing and adapting. You just can’t milk this too long. But you SHOULD milk it all you can. There is no sense in increasing demands on your adaptive abilities if they are not necessary yet. Get the most out of one weight first.
Secondarily, if you are going for mass, I like to go like so with a 10x3:
Workout 1:
set1: 3
set2: 3
set3: 3
set4: 3
set5: 3
set6: 3
set7: 3
set8: 2
set9: 2
set10: 2
Workout 2: I will ONLY go up in reps on set #8 and hit 3 reps.
Workout 3: I will ONLY go up in reps on set #9 and hit 3 reps.
Workout 4: I will ONLY go up in reps on set #10 and hit 3 reps.
Then for 2 or 3 times (workouts 5,6,7)I will stay with 10x3 and get comfortable. I allow the weight to be “lighter” both physically by fully adapting to it and I allow it to be mentally “lighter” by gaining repeated confidence with it.
Then in a perfect world I continue my Helix as follows: (after the above)
Workout 8:
set 1: 4reps
set 2: 4reps
set 3-10: 3 reps.
Workout 9:
sets 1-4: 4reps
sets 5-10: 3reps
Workout 10:
sets 1-6: 4 reps
sets 7-10: 3 reps
Workout 11:
sets 1-8: 4 reps
sets 9,10: 3 reps
Workout 12: (apex moment)
Sets 1-10: 4 reps for all.
I then do this same Helix progression until I can hit 10x5. This is a GREAT mass and strength progression.
*Important note: If you feel fatigued at some point then hover for a few workouts before you begin to progress upward again. This takes a bit of intuition and self awareness.
Bodybuilders (especially new ones or enthusiastic ones) always want to increase something every time they hit the gym. This is based on the accurate understanding that there must be progressive overload to grow bigger and stronger. The problem is not with the principle, as the above is true and necessary. The problem is with the practice. Progressive overload is a concept that must be applied over the LONG haul. Milk a weight and then progress after a sensible time with it, not every trip to the gym. You cannot keep this pace for long if you try to beat yourself at every workout. Go slow and allow yourself to get maximum benefit from each range.
On the above workouts there are times when I CAN do more, but the question is SHOULD I do more. The answer: NO. Not if I’m still able to gain from the current level of stimulation. Train don’t strain.
And don’t worry, I’ve got more tricks up my sleeve too. 
Disc Hoss