I'm 26 and started noticing hair thinning 2 yrs go. Using Rogaine for last month, and have been seeing extreme shedding.

Yes, there can be increased shedding with Rogaine. Results typically take 6 months. I suggest seeing a hair loss expert now to evaluate and go over your condition and provide you information about your best treatment options. There are great non-invasive options like prp/progesterone which work well with Rogaine. Hair transplantation is an alternative. See an expert. Best, Dr. Emer

Rogaine will cause and can increase shedding initially. Once the shedding stops your hair should come back thicker than before. You need to use Rogaine for at least 6 months to see any results or determine if it is working for you.

If you have a loss on sides most probably you have a androgenetic type hair
loss. I dont advice to use finasteride because of
possible side effects and being under
the necessity of using that chemical for almost life long to stop hair
loss.You may start to use minoxidil %5 to thicken the crown area and stop hair loss.You
would better planning to have an
exam at hair loss expert for hair restoration surgery when you fell
uncomfortable about hair styling or total loss of hair..

Rogaine can cause shedding initially. It might be attributed to increase in the turn over of the cells. However, it will eventually stop and in most cases you may see some improvement in the volume and bulk of your hair in the area. 

It could be the Accutane, the Rogaine, or a combination of both. Generally speaking, if it's the Rogaine that's causing the shedding it should stop within a few weeks. If it continues past a month or two, then it could be a result of the Accutane.

Both Rogaine and Accutane can trigger shedding at the sides. You can buy a medicine dropper at the pharmacy and many pharmacists will give out free. That will help you assess what 1 mL of the medicine is. The shedding from Rogaine lasts 6-8 weeks. Shedding from Accutane is pretty rare (less than 2 % of all users get shedding), but that form of shedding will continue as long as you are on the medicine (if you are actually getting shedding from the Accutane).If your shedding persists, please see your physician for review. 

It is not unusual for any taking Minoxidil and to get shedding. When this happens, it often goes away in a couple of months and the slowly benefits appear