All of a sudden this rush of warm liquid coming down but stopped all at once afterwards

I am 55 years o!d birth no children and not sexual active, virgin. My cycle has been over about one year. All of a sudden this rush of warm liquid coming down but stopped all at once afterwards. I found I passed a clot. The next day it happened again but the clots were bigger and I was camping. All together I passed about a cup of clots. I was so drained even before it happen. I didn't feel Lome doing anything at all during that time. Now here it is 2 1/2 weeks and its starting again. I went to work out. Finally finished getting ready to get in then all of a sudden I passed a clot on the way to the pool. I had to change my clothes and it spoiled my day. After passing it I got nauseated and felt sick. But it stopped. I just don't know when its going to happen again. But when I sit down sometimes ii feel cramps or it feels like I have bad gas and in slite pain. Even when I do come out the pool a lot of times I feel cramps as if I'm going to come on my cycle. I have so many people telling me so many things, I don't know what to think?