You could greatly benefit from Prof. Leonard Susskind's lectures on quantum mechanics and QFT on Youtube (Standford university's channel), which are very accessible. A great physicist who happens to be a great teacher and who gets all the deep interconnections involved. This is one playlist (he has many more): https://www.youtube.com/watch?v=JzhlfbWBuQ8&list=PL84C10A9CB...