Multiple Hamstring injuries

I’ve been lurking here for about a year, first time posting.
I like to lift, but have to run a lot for work. I decided to take back off running and concentrate on lifting for a while. I took my DL from 405 to 475 and my squat from 425 to 475 in that time. I started running again and within a week pulled my right hamstring (low and lateral portion). I took about 2 weeks off of all lower body except stretching. At the end of the 2 weeks I did a long slow run with no pain. 2 days later I did some light DL (315x3x5) with no pain. Today, I was deadlifting and getting gradually heavier with no pain. I went from 315 to 365 with no pain. I went for 405 and had no pain on my first rep. On my second rep I felt a pop in my left hamstring that was loud enough for other people in the gym to come over and ask me if I needed help. The pain is low and medial. I’m deployed so I haven’t been to a doc yet.

We are going to see how it looks in a week or so and go from there. But, I have hurt both hamstrings doing completely different exercises in a matter of three weeks. Obviously, I am going to be down for a couple of months, but any ideas on what caused my imbalance and how to correct it would be appreciated. The reps vary and I will occasionally add in different exercises, but the general framework of my routine looks something like this. I’m working out in a begged, borrowed, and stolen gym so we don’t have any machines for leg curls or presses etc.

Monday- 3 sets squat, 3 sets DB lunges, 3 sets RDL
Wed- DL and kettle bells swings
Friday-Repeat Monday