has my daughter got a medical problem

hi i have a 3year old daughter who was born 6 weeks early and only 4lbs she has speech and language problems she has very poor speech she is getting help for this my daughter has really bad behaviour problems where she will hit bite and hurt other children and adults even strangers she always like to repeat what she watches like peppa pig she will watch the same dvd every night she also like to touch and feel things with her hands and often puts it to her mouth or in her mouth when i speak to my daughter its like she is looking straight through me and she lacks eye contact she doesnt play with other children she tends to play along side them she is very hyper and sleeps very little i have two other children one age 4 and another age 1 my child is very different to others and i just know there is sumat wrong with her please help me