I don’t think you can learn gymnastics at home to a good standard. You need someone experienced to give you advice, special equipment to help you improve, a good space that is suitable to practice in, spotter (s). Also a mat isn't suitable for performing certain gymnastic skills on as it wont be soft enough and thick enough to stop injuries occurring especially when practising high level tumbles etc. There are many reasons why you cant learn gymnastics at home that's just a few of them. Why don't you rejoin your gym or join another? If you are overweight, most gyms do conditioning during the time you're there. If not, why don't you work out at home or join a fitness gym if you're old enough?
What you can learn at home is very limited. It is not just the risk of injury. It is the difficulty in developing good technique without proper instruction in what is a very technical sport.
Really if you want to do gymnastics you should join a class and damn what anyone else has to say. As you say, gymnastics is a tough sport and gymnasts have to be resilient enough to take knocks and set backs and meet those challenges with dedicated training and hard work to overcome them. That goes for the verbal slings and arrows too. Gymnasts have to be people who don't give up easily.
If you are at a beginner level and not a natural gymnast you should look for a rec class. In recreational gymnastics you train far less hours than competitve gymnasts do so if you really want to improve it helps a lot if you are put in some time on conditioning, improving your strength and flexibility at home. Your mat could be really useful for that.
Sure you can do tumbling by yourself at home, but you wont be doing anything properly and you would need a spot for more advanced skills. Gymnastics itself is not a sport you can teach yourself. But i would go to an open gym nearby where they have spots available for you!
Yea use your bed and a pole of your curtain.... so simple na???