Pulmonary Embolism Support Group
By far the most common form of pulmonary embolism is a thromboembolism, which occurs when a blood clot, generally a venous thrombus, becomes dislodged from its site of formation and embolizes to the arterial blood supply of one of the lungs. Symptoms may include difficulty breathing, pain during breathing, and more rarely circulatory instability and death.

I've had a DVT but never cramping at night. It was painful all day, red and swollen, which are the classic symptoms. There are those that don't have these symptoms and still have a DVT. If your concerned, maybe check with your doc.
Also, leg cramps could be a lot of things, including being dehydrated. Are you drinking enough.
But, after my PEs I got orthostatic hypotension, which made me feel horrible. One fix is to increase electrolytes and drink a lot more water. I've been taking magnesium every day, eating at least one banana daily, cutting back to one soda a day, and drinking lots of water (sometimes with electrolyte drink mixes). The orthostatic hypotesion went away, but I also discovered that I can stretch in bed again!
I don't know what it was, but adding electrolytes and more water made my leg cramps go away. It took a few months to kick in, but it is a nice side effect.
I had way more issues with my DVTs when I was standing up and moving around (meaning the blood could pool and back up in my leg behind the clots) than when I was laying down. And, it was pretty continuous, not just at night.
It is possible that leg cramps are related to clots, but I don't think there is a direct diagnostic correlation especially if you already know you have clots! I'd start kicking back with water and electrolytes and see how things go.
Again, my advice is get in to see your doctor, tell them the symptoms your having and any and ALL medications that you take.