Shortly after receiving the vaccination in May 2021, I started experiencing difficulty breathing (very winded doing normal daily activities, couldn't walk up a flight of stairs without gasping for breath). I started to being seen by a Pulmonologist who sent me for chest x-rays and CT scans. The only thing that I was told that I had fluid in my lungs and they were going to try to find out what was causing that. I went for an Echocardiogram which showed my heart was fine. On August 7, 2021 after several months of breathing difficulties and testing, I was on vacation with my family when I woke up with a swollen left ankle. I didn't think much of it, since I have arthritis and I went about my day. The next day it was even more swollen, so I called my pulmonologist to be safe. He suggested that I try to keep it elevated and stay off the leg as much as possible until I could be seen. The next day on August 9, 2021 I woke up to my entire leg from my groin to my toes being extremely swollen (left leg only). I again called my doctor and emailed him pictures and he said he wanted me to go to a facility to get a venous doppler ultrasound immediately.  I was able to get an appointment that same day and I left my trip with my kids in tow to go get the test done. After being seen, the radiologist wrote a report stating that there was no evidence of DVT or PE or any clotting in the leg (which was big mistake on the part of the radiology center-I will never be treated by them again). So, the next morning on August 10, 2021 I woke up and not only was my leg still huge and swollen, it was now dark purple and I couldn't bear any weight on that leg at all.  After a call to my doctor again, it was decided that I should go to an urgent care clinic. I decided to go to the ER since they would be more likely to be able to do whatever tests I needed. As I was leaving the campground to go to the ER I collapsed getting out of our camper and my sister (who I had called) called the campground front desk and the had an ambulance discharged. I was taken to Hospital and was admitted because after they ran a series of tests (including a venous doppler and CT scans) it was determined that I had two MASSIVE DVT blood clots in both of my legs and a chest xray showed that part of these had gone into my lungs. Because of the size of the clots, it was explained to my husband and I that they had been developing for quite some time and the initial chest xrays that I had done showing the fluid were the first indicators that I had clots forming in my body. These clots were the largest my ER team had seen in their 20+ years of practicing medicine. Because of the size of the clots, they were building for a many months and I was very lucky that I had my leg swell and turn purple otherwise I would have died from this. I stayed in the hospital for 5 days on heavy doses of meds and pain meds. Now it is a little over 2 months post hospital stay and I am still dealing with bad swelling in my left leg, mobility issues and pain. I needed to start walking with the assistance of a walker and my activity is still incredibly limited. I am going for my follow-up doppler ultrasound and chest CT next month to make sure they have shrunk significantly. I am now likely on blood thinners for the rest of my life. Before this, I never had a history of DVT or PE or any type of clots.