You are going to feel overwhelmed. It will happen. Likely, the feeling will come from a big project you’re really dedicated to that is running into some road blocks. It’s ok. You’re not the first and won’t be the last.
Find a way to get some perspective. What specifically is overwhelming you? Why? Once you’ve pinpointed those two answers you can figure out who or what can help alleviate those concerns. Then don’t be afraid to ask for help.
Other tips: Make lists. Get enough sleep. Turn work off. Prioritize. Delegate (if you can). What else?