How often can i strength train?

I normally do strength training exercises ( nothing elaborate, just regular squats, lunges, planks and some stretches ) after every run. And i run 5 times a week. I want to know how often should i do these exercises to get the best out of them. Is it possible I am doing them too often than needed? or what? 
I live in india. I love running. Unfortunately i find myself with lack of friends who share the same interest or a coach who could guide me. So i hope you guys could answer some of my questions.

I worked with a coach a couple years ago.  She put together a core/strength workout for me and recommended that I do it 3 days a week and reminded me to always take a rest day in between workouts.  I think recovery time is as important as training time.

Good luck.

Welcome!

For most of us, the question isn't "how often can I do strength training" but "how often do I have to do strength training." So you're already ahead of many of us.

I think Nancy's suggestion of three times per week is about right.

Mark, what if i like doing strength training 5 times a week. I always make sure i have 2 full days of rest in a week for recovery. My concern is regarding knee health. Can doing squats, lunges with a good form, 5 times a week hurt my knees? or will it strengthen my knees?

* All my strength training exercises are body weight, no added weight of dumbells or plates

It will strengthen your quads which will in turn help your knees greatly.  I think 3x per week is a good balance with running 5 days per week.  No matter your age or passion, we all need rest and recovery.

I understand now. This doubt that what if I'm o tiring, exhausting my muscles, has been on my mind for a long time. Never could find someone to guide me. Thank you so much for clearing this up for me. 

One last question. I'll strength train 3 days from now on. But you see I have this pre and post run warmup routine which has reverse lunges ( 10 - 15 reps), squats ( 10 reps), high kicks (20 reps), high knees ( 100 reps this one I only do pre run). About the rest of the 2 days that im not strentgh training, can\should I be do all these warm up routines ( considering they all include working quads, knees as well) on those days?

Absolutely!  We should all be as diligent with them!