GA pilot reported they had a near mid air collision with another aircraft while making a left bank turn after climbing heading to traffic pattern altitude. ATC notified them they had cut in front of traffic that was also on downwind.

Narrative

I was doing traffic pattern; take off; and landing practice at ABE solo. My last landing I performed a touch and go. Conditions were VMC with 10 SM of visibility and an overcast layer at 10;000 ft. However; the overcast layer had dark clouds and lighting was dimmer than normal. As I was in the climb on runway heading to traffic pattern altitude. I was instructor to follow Aircraft Z on downwind. I saw Aircraft Z turning on downwind and proceeded to follow that Aircraft Z I had in sight. I was unaware that there was another aircraft that had an extended upwind that was also on downwind. Being in a left bank attitude; visibility to the right was obstructed and I did not see Aircraft Y. After completing my turn into the downwind; I was notified by ATC that I cut in front of traffic. I do not recall hearing that second aircraft in the traffic pattern being directed to turn crosswind or downwind and I do not recall hearing that traffic (me) was in sight of other aircraft. After being notified I cut in front of traffic; I immediately admitted my error and apologized to ATC. I should have been more vigilant in monitoring other ATC communications; and I should have rechecked my right side before turning into the crosswind and downwind. Prior to the incident; I was the only aircraft in the pattern and was in a groove of just taking off and landing. I decreased my vigilance. Going forward; I will closely monitor all traffic communications; take an extra few seconds to thoroughly scan the side that will become a blind side; and clarify with ATC which aircraft I am to follow if directed to follow another aircraft in the pattern as well as keeping my vigilance at a maximum manner.