That sucks bud I've had that a few times. Your quads are made up of a group of muscles but only 1 of them, rectus femoris crosses over the hip joint. So during hip flexion on the leg press this can take some heavy strain and get injured quite easily when maxing out on the weight.
This muscle is not used as much as the other quad muscles during the squat, so it is easy for this to become a weak point and develop a strength imbalance in your quad muscles making you more prone to injury when you leg press heavy. Especially because you generally load more weight on the leg press.
It sounds like you have pain where the muscle is joined to the tendon so take it easy for 2 weeks. Tendons take longer to heal than muscle. You might feel fine with most leg movements with a rectus femoris strain but don't let that fool you to thinking it's not important to take it easy. I've strained this quite badly before by underestimating slight pain.