RC is a function of SP. If you have sufficient SP like to 20 to 30 SP you can manage your daily activity smoothly. In the following ways, you can recharge  your RC immediately.

1. You should recharge it immediately by powering up your account with some Steem. I think 20 to 30 SP will be sufficient for daily activity in steemit and other dApps.
2. You can also take delegated SP from Minnowbooster from their Direct Lease Market and also from Blockctrades.us. That will do fine for you to recharge your RC immediately. But that will cost you some steem. 
3. There are also some philanthropist person available in steem blockchain. They are really visionary and want to help good active people who on daily basis engage in steemit platform. They really want this platform to grow big. One of such person is @crypto.piotr. I was also exhausted with my RCs and with his help I got it recharged immediately and now being able to engage on daily basis. He has delegated me 40 SP and he will support me till Feb 2019, but I think before that I will have sufficient SP and I will tell him to undelegate and help some other needy people like you. You can contact him by sending a memo or by commenting on his post. I think he is quite active in steemit and within same day, you will get a reply and he may consider your request. But remember he supports active people and who posts and engage productively on steem blockchain. He does not support plagiarist & spammer. So be careful about this. 
4. You can also post a blog and seek for a help of 20 to 30 SP and if some generous people will come across your blog, they might consider you to help with some delegated SP.

Resource Credits is what replaced the bandwidth that the Steem blockchain. The Steem blockchain recently hard forked to version 20.0 of Steem the software about 3 months ago. This new upgrade removed the bandwidth system and replaced it with a new system called resource credits. This new system has caused some confusion among many Steem users since they weren’t able to post in steemit.

so when ever you run out of resource credit and you want to post on steemit or any other steemit D-apps, you just have to recharge your Rc or get your RC up. so in order to post on steemit or D-apps , you have to get more resource credit through the following;

1. buying of steem power

2. waiting until your resource credit recharges

3. Holding more steem power increases your resources credit

4. waiting until network usage decreses

i hope this information is useful

Basically you can either wait to recharge, or buy more Steem Power to have more RC (Resource Credits).

You can see how much RC (Resource Credits) you have and how much is your current RC (Resource Credits) recharge rate on the following link: https://steemd.com/@groynes

According to Steemd, you currently (2018.12.24, 14:33 CET) have 25.50% (1.1M /4.3M) RC (Resource Credits). 100% recharged in 3 days. Your recharge rate is 0.86M per day.

Well the usual thing many people do is to wait for the resource credit to recharge back automatically after few days..

But i believe the best action to take when you have exhausted your resource credits and you want to urgently comment on steemit is that you

should power up your steem wallet and your resource credits will increase and allow you to comment and the amount of resource credits you have will determine how many comments you can make....