Ankle sprain 6 weeks ago, no fracture. i was able to walk okay-ish in the second week, now i can walk perfectly, can do sit-ups but that hurts a little, extreme movement, a little loose and pull from jump hurts. i want to regain strength, what to do?

You are correct after any injury strengthening of the area is very important and protecting yourself from further injury. I would seek out a physical therapist and get a structured strengthening program for your ankle. If the ligaments are weak the only thing protecting your ankle are your muscles. ankle braces are appropriate during the strengthening program to protect yourself