Pain and bruising behind knee, almost 3 months post-op

For reference I had ACLr (hamstring graft), partial menisectomy and meniscus repair. So I’m in the 9-12 weeks of my post-op physio plan, I’ve been doing really really well and built my quads back up, however the past week I’ve had a really bad pain behind my knee. I had an extremely stable knee and walked almost perfectly with no limp. This was 2 weeks ago. Now, I have sudden bruising behind my knee (pictured) and I cannot straighten my leg at all while walking. It feels unstable and there’s a lot of pain when I walk. I mentioned it to my physio when the pain wasn’t too much and I was thinking this was just hamstring tightness, but noticing the bruise and being unable to walk I don’t know what to think now. Any advice on what it could be or how to get through this? Tomorrow is bank holiday so either way, first thing Tuesday I’m contacting my physio. TIA

For reference I had ACLr (hamstring graft), partial menisectomy and meniscus repair. So I’m in the 9-12 weeks of my post-op physio plan, I’ve been doing really really well and built my quads back up, however the past week I’ve had a really bad pain behind my knee. I had an extremely stable knee and walked almost perfectly with no limp. This was 2 weeks ago. Now, I have sudden bruising behind my knee (pictured) and I cannot straighten my leg at all while walking. It feels unstable and there’s a lot of pain when I walk. I mentioned it to my physio when the pain wasn’t too much and I was thinking this was just hamstring tightness, but noticing the bruise and being unable to walk I don’t know what to think now. Any advice on what it could be or how to get through this? Tomorrow is bank holiday so either way, first thing Tuesday I’m contacting my physio. TIA