Hip Flexor Injury

Bit of history.

About two years ago I was sleeping after playing touch football two hours earlier and woke up with a horrible pain in my hip. I don't remember doing something specifically to injure it, scans were done and I was told it was a bad strain of my hip flexor. I did some physio (which didn't seem to help), so I just rested it for a few weeks (i.e. did absolutely nothing at the gym) and it seemed to get better on its own. During my AFL season, it flared up a few times, which I treated with anti-inflammatories and massage.

Started training properly again in August last year, really upping the intensity around Christmas time. New years day, I pulled something so bad I couldn't walk without pain. More scans, physio, rest and diagnosis - another bad strain. I took it really easy for four weeks, then did a 10km run at the end of January and it was fine. I've just started to get back up to training daily (was training twice a day) and it's flared up again.

I've been back to the physio, gotten more exercises to do to strengthen my glutes and hip flexor to prevent this from happening yet again.

My question is - what can I do in the mean time? I'm hating not exercising that much, it is so frustrating. I don't have access to a pool for the next 2 1/2 months. I've been using the elliptical trainer at the gym and kept doing isolated weights, but it just doesn't feel like it's enough. I miss doing squats and lunges - is there other exercises I can do to train these areas that don't utilise the hip flexor too much? I love cross-fit style circuits and am finding my exercise routine quite boring without them. Suggestions?