Guys, I have been grinding 1400-1700 rated problem since 2-3 months but I was so depressed as I could not become a specialist. Finally, the day has come I solved 6 problems on yesterday's div3. I became specialist! Anyone please give me some suggestion to improve further.

Hi it's been two-three months since I have started doing cp. i am quite comfortable while solving div 3,div 4 problems and I am able to solve 4-5 problems within the contest. and my rating increases easily in div3 and div4 but when it comes to div2 i often struggle in solving div2 B despite practicing the problems rated 1200-1500 around 30 problems in each range I still struggle in div2, as a result my rating always falls down. What should i do? should i only use div3 and div4 until i become specialist. Please suggest me some way to overcome this problem.