Can anyone help me

I gave birth 13 weeks ago and the last 5 weeks I have been going to the gym.
I went last night and I always start on the running machine, and I always power walk as I'm not a runner, but last night a had the urge to run, I slowly ran for 10 minutes (which I have never ran that long in about 6 years)
After those 10 minutes I got really bad cramps in my vagina area like everything was stiff and knotted.
So I was wondering is this because I am using those muscles when running and they are not used to it or is it because I gave birth 13 weeks ago and doing ''intence'' exercise to early.

Please can someone help :)
Thanks

The cramps are likely because your uterus is going back to its normal size before the pregnancy. They are normal although I'm unsure whether exercise would aggravate the situation. Like any other healing process, it's best to start soft and gradually move up.

Make sure you hydrate yourself well a few hours in advance before exercising...
And eat plenty of fresh fruit and vegetables for potassium...

Dehydration and lack of potassium is the #1 cause of cramps... no matter where they are...

As for the birth related issues, ask your doctor, but s/he will probably tell you to take it slow...

As a fitness trainer, I'm thinking as long as you take it up to the point of where you might start to feel a cramp then back off so you don't get one, that will be the most quick way back to your exercise routine... :)

Every workout will get better and better with time with fewer cramps if you continue to hydrate and eat plenty of fruits and veggies...