Alternating reverse lunges with breathing.
Breathe in deeply, arch back and push out chest. Breath out while keeping chest up and back arched.
Lower yourself while inhaling deeply, focus on pushing the back foot rearward and keeping trunk upright, chest up, and back arched.
Feel the stretch in your hips and readjust if you need to. At this point you can exhale and breathe in deep again while keeping your chest up and back arched.
Push through your entire front foot and exhale as you go through the sticking point. At the top exhale fully.
Repeat with other leg.
Over time you will be able to remove the extra breathing, but if you need to reset your position at the top or bottom, the extra breathing helps. Do not try to go to failure, you are better off leaving reps in the hole and focusing on form. Simply do more sets if you have to. This also works well as a warm up.
Here is an article on breathing:
You obviously have flexibility issues, this drill/exercise I recommended will fix that fast, do 30-50 reps per leg each day in sets of 5 reps per leg. You can split it into 2 miniworkouts. I guarantee that in a week or two your flexibility will drastically improve as will your muscle control. BTW I parallel squatted nearly twice what you did and still could not do a proper bodyweight squat when I was young and dumb (just so you know I am not talking out my ass), I was around 180.
Also foam rolling any tight muscles or spots will go a long way in keeping you mobile.